diff --git a/Tsi1.Api/Tsi1.Api/Controllers/CommunicationController.cs b/Tsi1.Api/Tsi1.Api/Controllers/CommunicationController.cs
new file mode 100644
index 0000000000000000000000000000000000000000..7cdda5f21891cb2f1727dc66ec91cfe8e1b486a3
--- /dev/null
+++ b/Tsi1.Api/Tsi1.Api/Controllers/CommunicationController.cs
@@ -0,0 +1,99 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Security.Claims;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Tsi1.BusinessLayer.Dtos;
+using Tsi1.BusinessLayer.Helpers;
+using Tsi1.BusinessLayer.Interfaces;
+
+namespace Tsi1.Api.Controllers
+{
+    [Route("api/[controller]")]
+    [ApiController]
+    public class CommunicationController : ControllerBase
+    {
+        private readonly ICommunicationService _communicationService;
+
+        public CommunicationController(ICommunicationService communicationService)
+        {
+            _communicationService = communicationService;
+        }
+
+        [Authorize(Roles = UserTypes.FacultyAdmin + ", " + UserTypes.UdelarAdmin)]
+        [HttpPost("CreateCourseCommunication/{courseId}")]
+        public async Task<IActionResult> CreateCourseCommunication(CommunicationCreateDto newCommunication, int courseId)
+        {
+            var tenantId = int.Parse(HttpContext.User.Claims.FirstOrDefault(x => x.Type == "TenantId").Value);
+            var validationResult = await _communicationService.TenantValidation(tenantId, courseId);
+
+            if (validationResult.HasError)
+            {
+                return BadRequest(validationResult.Message);
+            }
+
+            var result = await _communicationService.Create(newCommunication, courseId);
+
+            if (result.HasError)
+            {
+                return BadRequest(result.Message);
+            }
+
+            return Ok();
+        }
+
+        [Authorize(Roles = UserTypes.FacultyAdmin + ", " + UserTypes.UdelarAdmin)]
+        [HttpPost("CreateTenantCommunication")]
+        public async Task<IActionResult> CreateTenantCommunication(CommunicationCreateDto newCommunication, int tenantId)
+        {
+            var userType = HttpContext.User.Claims.FirstOrDefault(x => x.Type == ClaimTypes.Role).Value;
+            if (userType == UserTypes.FacultyAdmin)
+            {
+                tenantId = int.Parse(HttpContext.User.Claims.FirstOrDefault(x => x.Type == "TenantId").Value);
+            }
+
+            newCommunication.IsGlobal = true;
+            var result = await _communicationService.Create(newCommunication, tenantId);
+
+            if (result.HasError)
+            {
+                return BadRequest(result.Message);
+            }
+
+            return Ok();
+        }
+
+        [Authorize(Roles = UserTypes.Student)]
+        [HttpGet("GetMyCommunications")]
+        public async Task<IActionResult> GetMyCommunications()
+        {
+            var userId = int.Parse(HttpContext.User.Claims.FirstOrDefault(x => x.Type == "Id").Value);
+
+            var result = await _communicationService.GetMyCommunications(userId);
+
+            if (result.HasError)
+            {
+                return BadRequest(result.Message);
+            }
+
+            return Ok(result.Data);
+        }
+
+        [Authorize(Roles = UserTypes.FacultyAdmin + ", " + UserTypes.UdelarAdmin)]
+        [HttpDelete("Delete/{communicationId}")]
+        public async Task<IActionResult> Delete(int communicationId)
+        {
+            var result = await _communicationService.Delete(communicationId);
+
+            if (result.HasError)
+            {
+                return BadRequest(result.Message);
+            }
+
+            return Ok();
+        }
+    }
+}
diff --git a/Tsi1.Api/Tsi1.Api/SignalR/ChatHub.cs b/Tsi1.Api/Tsi1.Api/SignalR/ChatHub.cs
index 0c54af61a8bd5ac751eec8dd173a9f1140b4f5c8..575b05897d81008f78475837aee031ca50e3ae94 100644
--- a/Tsi1.Api/Tsi1.Api/SignalR/ChatHub.cs
+++ b/Tsi1.Api/Tsi1.Api/SignalR/ChatHub.cs
@@ -66,6 +66,8 @@ namespace Tsi1.Api.SignalR
             var userId = int.Parse(Context.User.Claims.FirstOrDefault(x => x.Type == "Id").Value);
             var tenantId = int.Parse(Context.User.Claims.FirstOrDefault(x => x.Type == "TenantId").Value);
 
+            newMessage.TenantId = tenantId;
+
             if (userId == newMessage.ReceiverId)
                 throw new HubException("You cannot send messages to yourself");
 
@@ -93,41 +95,18 @@ namespace Tsi1.Api.SignalR
             await Clients.Group(groupName).SendAsync("NewMessage", messageDto);
         }
 
-        private async Task<Group> AddToGroup(string groupName)
+        private async Task<bool> AddToGroup(string groupName)
         {
-            var group = await _chatService.GetGroupByName(groupName);
-
-            if (group == null)
-            {
-                throw new HubException($"No existe el grupo {groupName}");
-            }
-
             var userId = int.Parse(Context.User.Claims.FirstOrDefault(x => x.Type == "Id").Value);
 
-            var connection = new Connection
-            {
-                ConnectionId = Context.ConnectionId,
-                UserId = userId,
-            };
-
-            if (group == null)
-            {
-                group = new Group
-                {
-                    Name = groupName,
-                };
-            }
-
-            group.Connections.Add(connection);
-
-            var result = await _chatService.CreateGroup(group);
+            var result = await _chatService.CreateGroup(groupName, Context.ConnectionId, userId);
 
             if (result.HasError)
             {
-                throw new HubException($"Error al crear el grupo {group}");
+                throw new HubException($"Error al crear el grupo {groupName}");
             }
 
-            return group;
+            return true;
         }
 
         private async Task<bool> RemoveFromGroup()
diff --git a/Tsi1.Api/Tsi1.Api/Startup.cs b/Tsi1.Api/Tsi1.Api/Startup.cs
index 3f9deee93729fd9e50277d2ffd69fd8f64aa154d..90bca24e58e0280359f8a1a93b2ecf7f173109cb 100644
--- a/Tsi1.Api/Tsi1.Api/Startup.cs
+++ b/Tsi1.Api/Tsi1.Api/Startup.cs
@@ -93,6 +93,10 @@ namespace Tsi1.Api
             services.AddScoped<ISectionItemTypeService, SectionItemTypeService>();
             services.AddScoped<IDataLoad, DataLoad>();
             services.AddScoped<ISurveyService, SurveyService>();
+            services.AddScoped<ICommunicationService, CommunicationService>();
+            services.AddScoped<IChatService, ChatService>();
+
+            services.AddSingleton<PresenceTracker>();
 
             services.Configure<MailSettings>(Configuration.GetSection("MailSettings"));
             services.AddScoped<IEmailService, EmailService>();
diff --git a/Tsi1.Api/Tsi1.BusinessLayer/Dtos/CommunicationCreateDto.cs b/Tsi1.Api/Tsi1.BusinessLayer/Dtos/CommunicationCreateDto.cs
new file mode 100644
index 0000000000000000000000000000000000000000..24f82ce35ee326a372b7ed5ac182fa25c546816b
--- /dev/null
+++ b/Tsi1.Api/Tsi1.BusinessLayer/Dtos/CommunicationCreateDto.cs
@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Text.Json.Serialization;
+
+namespace Tsi1.BusinessLayer.Dtos
+{
+    public class CommunicationCreateDto
+    {
+        public string Text { get; set; }
+
+        [JsonIgnore]
+        public bool IsGlobal { get; set; }
+
+        public DateTime ValidUntil { get; set; }
+    }
+}
diff --git a/Tsi1.Api/Tsi1.BusinessLayer/Dtos/CommunicationPreviewDto.cs b/Tsi1.Api/Tsi1.BusinessLayer/Dtos/CommunicationPreviewDto.cs
new file mode 100644
index 0000000000000000000000000000000000000000..6945046e32173939c506438bacf7e0d706e293ef
--- /dev/null
+++ b/Tsi1.Api/Tsi1.BusinessLayer/Dtos/CommunicationPreviewDto.cs
@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Tsi1.BusinessLayer.Dtos
+{
+    public class CommunicationPreviewDto
+    {
+        public int Id { get; set; }
+
+        public string Text { get; set; }
+    }
+}
diff --git a/Tsi1.Api/Tsi1.BusinessLayer/Helpers/ErrorMessages.cs b/Tsi1.Api/Tsi1.BusinessLayer/Helpers/ErrorMessages.cs
index c61742af40d30ff6d921347d857a16d4487272e6..b049c0244d6ec63c379544c1c0da7f90a475a6ad 100644
--- a/Tsi1.Api/Tsi1.BusinessLayer/Helpers/ErrorMessages.cs
+++ b/Tsi1.Api/Tsi1.BusinessLayer/Helpers/ErrorMessages.cs
@@ -61,5 +61,8 @@ namespace Tsi1.BusinessLayer.Helpers
         public const string SurveyHasNoQuestions = "La encuesta no tiene preguntas";
         public const string InvalidSurvey = "La encuesta no pertenece a la facultad con id '{0}'";
         public const string SurveyResponseAlreadyExist = "El usuario '{0}' ya completo la encuesta '{1}'";
+
+        public const string CommunicationDoesNotExist = "La comunicación con id '{0}' no existe";
+        public const string InvalidTenant = "El usuario no pertenece a la facultad con id '{0}'";
     }
 }
diff --git a/Tsi1.Api/Tsi1.BusinessLayer/Helpers/MappingProfile.cs b/Tsi1.Api/Tsi1.BusinessLayer/Helpers/MappingProfile.cs
index a3e0c6d914391310540feb35564ed2c8638a3f9e..d56100cf0435165372be069b17082b2438628864 100644
--- a/Tsi1.Api/Tsi1.BusinessLayer/Helpers/MappingProfile.cs
+++ b/Tsi1.Api/Tsi1.BusinessLayer/Helpers/MappingProfile.cs
@@ -49,6 +49,8 @@ namespace Tsi1.BusinessLayer.Helpers
             CreateMap<SurveyResponse, SurveyResponseDetailDto>();
             CreateMap<SurveyAnswer, SurveyAnswerDetailDto>();
             CreateMap<SurveyAnswer, SurveyAnswerCreateDto>();
+            CreateMap<Communication, CommunicationCreateDto>();
+            CreateMap<Communication, CommunicationPreviewDto>();
             CreateMap<AnswerOption, AnswerOptionDetailDto>();
 
             CreateMap<ForumCreateDto, Forum>();
@@ -88,6 +90,8 @@ namespace Tsi1.BusinessLayer.Helpers
             CreateMap<SurveyResponseDetailDto, SurveyResponse>();
             CreateMap<SurveyAnswerDetailDto, SurveyAnswer>();
             CreateMap<SurveyAnswerCreateDto, SurveyAnswer>();
+            CreateMap<CommunicationCreateDto, Communication>();
+            CreateMap<CommunicationPreviewDto, Communication>();
             CreateMap<AnswerOptionDetailDto, AnswerOption>();
         }
     }
diff --git a/Tsi1.Api/Tsi1.BusinessLayer/Interfaces/IChatService.cs b/Tsi1.Api/Tsi1.BusinessLayer/Interfaces/IChatService.cs
index cf332b0a11d11b5b77f9058d9d1a95488293b9ea..a79f4b1782a5111636d70efa79a199682db1816a 100644
--- a/Tsi1.Api/Tsi1.BusinessLayer/Interfaces/IChatService.cs
+++ b/Tsi1.Api/Tsi1.BusinessLayer/Interfaces/IChatService.cs
@@ -11,7 +11,7 @@ namespace Tsi1.BusinessLayer.Interfaces
     {
         Task<Group> GetGroupByName(string groupName);
 
-        Task<ServiceResult<Group>> CreateGroup(Group group);
+        Task<ServiceResult<bool>> CreateGroup(string groupName, string connectionId, int userId);
 
         Task<bool> RemoveConnectionFromGroup(string connectionId);
     }
diff --git a/Tsi1.Api/Tsi1.BusinessLayer/Interfaces/ICommunicationService.cs b/Tsi1.Api/Tsi1.BusinessLayer/Interfaces/ICommunicationService.cs
new file mode 100644
index 0000000000000000000000000000000000000000..ce39e10fe3c8219d4b17d1316779a3b066027cdc
--- /dev/null
+++ b/Tsi1.Api/Tsi1.BusinessLayer/Interfaces/ICommunicationService.cs
@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Threading.Tasks;
+using Tsi1.BusinessLayer.Dtos;
+using Tsi1.BusinessLayer.Helpers;
+
+namespace Tsi1.BusinessLayer.Interfaces
+{
+    public interface ICommunicationService
+    {
+        Task<ServiceResult<bool>> Create(CommunicationCreateDto newCommunication, int id);
+
+        Task<ServiceResult<bool>> Delete(int communicationId);
+
+        Task<ServiceResult<List<CommunicationPreviewDto>>> GetMyCommunications(int userId);
+
+        Task<ServiceResult<bool>> TenantValidation(int tenantId, int courseId);
+    }
+}
diff --git a/Tsi1.Api/Tsi1.BusinessLayer/Services/ChatService.cs b/Tsi1.Api/Tsi1.BusinessLayer/Services/ChatService.cs
index 4e4ac8e76aaca0017a0d35dca73cd1e57503da3e..93573625ea418e32ad924cf5124c8e93028e6689 100644
--- a/Tsi1.Api/Tsi1.BusinessLayer/Services/ChatService.cs
+++ b/Tsi1.Api/Tsi1.BusinessLayer/Services/ChatService.cs
@@ -18,11 +18,35 @@ namespace Tsi1.BusinessLayer.Services
         {
             _tsi1Context = tsi1Context;
         }
-        public async Task<ServiceResult<Group>> CreateGroup(Group group)
+
+        public async Task<ServiceResult<bool>> CreateGroup(string groupName, string connectionId, int userId)
         {
-            var result = new ServiceResult<Group>();
+            var result = new ServiceResult<bool>();
+            var existingGroup = true;
+            var group = await this.GetGroupByName(groupName);
+
+            if (group == null)
+            {
+                existingGroup = false;
+                group = new Group
+                {
+                    Name = groupName,
+                };
+            }
 
-            _tsi1Context.Groups.Add(group);
+            var connection = new Connection
+            {
+                ConnectionId = connectionId,
+                UserId = userId,
+            };
+
+            group.Connections.Add(connection);
+
+            if (!existingGroup)
+            {
+                _tsi1Context.Groups.Add(group);
+            }
+            
             try
             {
                 await _tsi1Context.SaveChangesAsync();
@@ -51,6 +75,8 @@ namespace Tsi1.BusinessLayer.Services
             if (connection != null)
             {
                 connection.Group = null;
+                _tsi1Context.Connections.Remove(connection);
+
                 await _tsi1Context.SaveChangesAsync();
             }
 
diff --git a/Tsi1.Api/Tsi1.BusinessLayer/Services/CommunicationService.cs b/Tsi1.Api/Tsi1.BusinessLayer/Services/CommunicationService.cs
new file mode 100644
index 0000000000000000000000000000000000000000..9f7e31be67ce597fbf52dd4a9af7ff9dfcb616a1
--- /dev/null
+++ b/Tsi1.Api/Tsi1.BusinessLayer/Services/CommunicationService.cs
@@ -0,0 +1,139 @@
+using AutoMapper;
+using Microsoft.EntityFrameworkCore;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Tsi1.BusinessLayer.Dtos;
+using Tsi1.BusinessLayer.Helpers;
+using Tsi1.BusinessLayer.Interfaces;
+using Tsi1.DataLayer;
+using Tsi1.DataLayer.Entities;
+
+namespace Tsi1.BusinessLayer.Services
+{
+    public class CommunicationService : ICommunicationService
+    {
+        private readonly Tsi1Context _context;
+        private readonly IMapper _mapper;
+
+        public CommunicationService(Tsi1Context context, IMapper mapper)
+        {
+            _context = context;
+            _mapper = mapper;
+        }
+
+        public async Task<ServiceResult<bool>> Create(CommunicationCreateDto newCommunication, int id)
+        {
+            var result = new ServiceResult<bool>();
+            var isGlobal = newCommunication.IsGlobal;
+            var commmunication = _mapper.Map<Communication>(newCommunication);
+
+            var validationResult = await this.CreateValidation(id, isGlobal, commmunication);
+
+            if (validationResult.HasError)
+            {
+                return validationResult;
+            }
+
+            _context.Communications.Add(commmunication);
+
+            await _context.SaveChangesAsync();
+
+            return result;
+        }
+
+        public async Task<ServiceResult<bool>> Delete(int communicationId)
+        {
+            var result = new ServiceResult<bool>();
+            var commmunication = await _context.Communications.FirstOrDefaultAsync(x => x.Id == communicationId);
+
+            if (commmunication == null)
+            {
+                result.HasError = true;
+                result.AddMessage(string.Format(ErrorMessages.CommunicationDoesNotExist, communicationId));
+                return result;
+            }
+
+            _context.Communications.Remove(commmunication);
+            await _context.SaveChangesAsync();
+
+            return result;
+        }
+
+        public async Task<ServiceResult<List<CommunicationPreviewDto>>> GetMyCommunications(int userId)
+        {
+            var result = new ServiceResult<List<CommunicationPreviewDto>>();
+            var user = await _context.Users.AsNoTracking().FirstOrDefaultAsync(x => x.Id == userId);
+
+            var courseIds = await _context.StudentCourses
+                .AsNoTracking()
+                .Where(x => x.StudentId == user.StudentId)
+                .Select(x => x.CourseId)
+                .ToListAsync();
+
+            var communications = await _context.Communications
+                .AsNoTracking()
+                .Include(x => x.Tenant)
+                .Include(x => x.Course)
+                .Where(x => (x.Tenant.Id == userId || courseIds.Contains(x.Course.Id))
+                    && x.ValidUntil >= DateTime.Now)
+                .ToListAsync();
+
+            result.Data = _mapper.Map<List<CommunicationPreviewDto>>(communications);
+
+            return result;
+        }
+
+        public async Task<ServiceResult<bool>> TenantValidation(int tenantId, int courseId)
+        {
+            var result = new ServiceResult<bool>();
+
+            var tenantAdmin = await _context.Tenants.AsNoTracking().FirstOrDefaultAsync(x => x.Name == TenantAdmin.Name);
+            var course = await _context.Courses.AsNoTracking().FirstOrDefaultAsync(x => x.Id == courseId);
+
+            if (tenantAdmin.Id != tenantId)
+            {
+                result.HasError = course.TenantId != tenantId;
+                result.AddMessage(string.Format(ErrorMessages.InvalidTenant, course.TenantId));
+            }
+
+            return result;
+        }
+
+        private async Task<ServiceResult<bool>> CreateValidation(int id, bool isGlobal, Communication commmunication)
+        {
+            var result = new ServiceResult<bool>();
+
+            if (isGlobal)
+            {
+                var tenant = await _context.Tenants.FirstOrDefaultAsync(x => x.Id == id && x.Name != TenantAdmin.Name);
+
+                if (tenant == null)
+                {
+                    result.HasError = true;
+                    result.AddMessage(string.Format(ErrorMessages.TenantDoesNotExist, id));
+                    return result;
+                }
+
+                commmunication.Tenant = tenant;
+            }
+            else
+            {
+                var course = await _context.Courses.FirstOrDefaultAsync(x => x.Id == id);
+
+                if (course == null)
+                {
+                    result.HasError = true;
+                    result.AddMessage(string.Format(ErrorMessages.CourseDoesNotExist, id));
+                    return result;
+                }
+
+                commmunication.Course = course;
+            }           
+
+            return result;
+        }
+    }
+}
diff --git a/Tsi1.Api/Tsi1.DataLayer/Entities/Communication.cs b/Tsi1.Api/Tsi1.DataLayer/Entities/Communication.cs
new file mode 100644
index 0000000000000000000000000000000000000000..67fe974db417548c38b632c510cf3dccc0180f33
--- /dev/null
+++ b/Tsi1.Api/Tsi1.DataLayer/Entities/Communication.cs
@@ -0,0 +1,21 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Tsi1.DataLayer.Entities
+{
+    public class Communication
+    {
+        public int Id { get; set; }
+
+        public string Text { get; set; }
+
+        public bool IsGlobal { get; set; }
+
+        public DateTime ValidUntil { get; set; }
+
+        public Course Course { get; set; }
+
+        public Tenant Tenant { get; set; }
+    }
+}
diff --git a/Tsi1.Api/Tsi1.DataLayer/Entities/Course.cs b/Tsi1.Api/Tsi1.DataLayer/Entities/Course.cs
index 80c429198380aaf675c92b39bd57261dbda4fc5e..f7efedf6afcfa34052001aa393799e23773d8eb3 100644
--- a/Tsi1.Api/Tsi1.DataLayer/Entities/Course.cs
+++ b/Tsi1.Api/Tsi1.DataLayer/Entities/Course.cs
@@ -11,6 +11,7 @@ namespace Tsi1.DataLayer.Entities
             StudentCourses = new HashSet<StudentCourse>();
             ProfessorCourses = new HashSet<ProfessorCourse>();
             Sections = new HashSet<Section>();
+            Communications = new HashSet<Communication>();
         }
 
         public int Id { get; set; }
@@ -22,5 +23,7 @@ namespace Tsi1.DataLayer.Entities
         public ICollection<StudentCourse> StudentCourses { get; set; }
         public ICollection<ProfessorCourse> ProfessorCourses { get; set; }
         public ICollection<Section> Sections { get; set; }
+
+        public ICollection<Communication> Communications { get; set; }
     }
 }
diff --git a/Tsi1.Api/Tsi1.DataLayer/Entities/Tenant.cs b/Tsi1.Api/Tsi1.DataLayer/Entities/Tenant.cs
index 0a153f83884dc7a09793b79647cb6dc174309b54..a146909738b7f82989d3e8b541bcad8996e89cc6 100644
--- a/Tsi1.Api/Tsi1.DataLayer/Entities/Tenant.cs
+++ b/Tsi1.Api/Tsi1.DataLayer/Entities/Tenant.cs
@@ -13,6 +13,7 @@ namespace Tsi1.DataLayer.Entities
             Students = new HashSet<Student>();
             Users = new HashSet<User>();
             Surveys = new HashSet<Survey>();
+            Communications = new HashSet<Communication>();
         }
 
         public int Id { get; set; }
@@ -24,5 +25,7 @@ namespace Tsi1.DataLayer.Entities
         public ICollection<Student> Students { get; set; }
         public ICollection<User> Users { get; set; }
         public ICollection<Survey> Surveys { get; set; }
+
+        public ICollection<Communication> Communications { get; set; }
     }
 }
diff --git a/Tsi1.Api/Tsi1.DataLayer/EntityConfiguration/CommunicationConfiguration.cs b/Tsi1.Api/Tsi1.DataLayer/EntityConfiguration/CommunicationConfiguration.cs
new file mode 100644
index 0000000000000000000000000000000000000000..ae75b956b610fbb58fd31143f68d4d9758379252
--- /dev/null
+++ b/Tsi1.Api/Tsi1.DataLayer/EntityConfiguration/CommunicationConfiguration.cs
@@ -0,0 +1,26 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+using System;
+using System.Collections.Generic;
+using System.Text;
+using Tsi1.DataLayer.Entities;
+
+namespace Tsi1.DataLayer.EntityConfiguration
+{
+    public class CommunicationConfiguration : IEntityTypeConfiguration<Communication>
+    {
+        public void Configure(EntityTypeBuilder<Communication> builder)
+        {
+            builder.HasKey(x => x.Id);
+
+            builder.Property(x => x.Text)
+                .IsRequired()
+                .HasColumnType("character varying(1000)");
+
+            builder.Property(x => x.ValidUntil)
+                .IsRequired();
+
+            builder.HasIndex(x => x.ValidUntil);
+        }
+    }
+}
diff --git a/Tsi1.Api/Tsi1.DataLayer/Migrations/20201115152033_add-communication-entity.Designer.cs b/Tsi1.Api/Tsi1.DataLayer/Migrations/20201115152033_add-communication-entity.Designer.cs
new file mode 100644
index 0000000000000000000000000000000000000000..2f9418e96b9c9f650fb3eed5e56fcdd25bf9b630
--- /dev/null
+++ b/Tsi1.Api/Tsi1.DataLayer/Migrations/20201115152033_add-communication-entity.Designer.cs
@@ -0,0 +1,826 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+using Tsi1.DataLayer;
+
+namespace Tsi1.DataLayer.Migrations
+{
+    [DbContext(typeof(Tsi1Context))]
+    [Migration("20201115152033_add-communication-entity")]
+    partial class addcommunicationentity
+    {
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn)
+                .HasAnnotation("ProductVersion", "3.1.4")
+                .HasAnnotation("Relational:MaxIdentifierLength", 63);
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.AnswerOption", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(100)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Name");
+
+                    b.ToTable("AnswerOptions");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Communication", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<int?>("CourseId")
+                        .HasColumnType("integer");
+
+                    b.Property<int?>("TenantId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Text")
+                        .HasColumnType("text");
+
+                    b.Property<DateTime>("ValidUntil")
+                        .HasColumnType("timestamp without time zone");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CourseId");
+
+                    b.HasIndex("TenantId");
+
+                    b.ToTable("Communication");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Connection", b =>
+                {
+                    b.Property<string>("ConnectionId")
+                        .HasColumnType("text");
+
+                    b.Property<string>("GroupName")
+                        .HasColumnType("text");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("ConnectionId");
+
+                    b.HasIndex("GroupName");
+
+                    b.ToTable("Connections");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Course", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<bool>("IsTemplate")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<int>("TenantId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TenantId");
+
+                    b.HasIndex("Name", "TenantId")
+                        .IsUnique();
+
+                    b.ToTable("Courses");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.File", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<string>("Path")
+                        .IsRequired()
+                        .HasColumnType("character varying(1000)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Path")
+                        .IsUnique();
+
+                    b.ToTable("Files");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Forum", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(50)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Forums");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.ForumUser", b =>
+                {
+                    b.Property<int>("ForumId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("ForumId", "UserId");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("ForumUsers");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Group", b =>
+                {
+                    b.Property<string>("Name")
+                        .HasColumnType("text");
+
+                    b.HasKey("Name");
+
+                    b.ToTable("Groups");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Post", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<DateTime>("Date")
+                        .HasColumnType("timestamp without time zone");
+
+                    b.Property<int>("ForumId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Title")
+                        .IsRequired()
+                        .HasColumnType("character varying(100)");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId");
+
+                    b.HasIndex("ForumId", "Title")
+                        .IsUnique();
+
+                    b.ToTable("Posts");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.PostMessage", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Content")
+                        .IsRequired()
+                        .HasColumnType("character varying(10485760)");
+
+                    b.Property<DateTime>("Date")
+                        .HasColumnType("timestamp without time zone");
+
+                    b.Property<int>("PostId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("PostId");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("PostMessages");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Professor", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("IdentityCard")
+                        .IsRequired()
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<int>("TenantId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TenantId");
+
+                    b.HasIndex("IdentityCard", "TenantId")
+                        .IsUnique();
+
+                    b.ToTable("Professors");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.ProfessorCourse", b =>
+                {
+                    b.Property<int>("ProfessorId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("CourseId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("ProfessorId", "CourseId");
+
+                    b.HasIndex("CourseId");
+
+                    b.ToTable("ProfessorCourses");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Section", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<int>("CourseId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<int>("Order")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CourseId");
+
+                    b.ToTable("Sections");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SectionItem", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<int?>("FileId")
+                        .HasColumnType("integer");
+
+                    b.Property<int?>("ForumId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("Order")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("SectionId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("SectionItemTypeId")
+                        .HasColumnType("integer");
+
+                    b.Property<int?>("SurveyId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("FileId")
+                        .IsUnique();
+
+                    b.HasIndex("ForumId")
+                        .IsUnique();
+
+                    b.HasIndex("SectionId");
+
+                    b.HasIndex("SectionItemTypeId");
+
+                    b.HasIndex("SurveyId")
+                        .IsUnique();
+
+                    b.ToTable("SectionItems");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SectionItemType", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(100)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("SectionItemTypes");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Student", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<int>("Age")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("IdentityCard")
+                        .IsRequired()
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<int>("TenantId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TenantId");
+
+                    b.HasIndex("IdentityCard", "TenantId")
+                        .IsUnique();
+
+                    b.ToTable("Students");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.StudentCourse", b =>
+                {
+                    b.Property<int>("StudentId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("CourseId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("StudentId", "CourseId");
+
+                    b.HasIndex("CourseId");
+
+                    b.ToTable("StudentCourses");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Survey", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<bool>("IsGlobal")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<int?>("TenantId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Name");
+
+                    b.HasIndex("TenantId");
+
+                    b.ToTable("Surveys");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SurveyAnswer", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<int>("AnswerOptionId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("SurveyQuestionId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("SurveyResponseId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("AnswerOptionId");
+
+                    b.HasIndex("SurveyQuestionId");
+
+                    b.HasIndex("SurveyResponseId");
+
+                    b.ToTable("SurveyAnswers");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SurveyQuestion", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Question")
+                        .IsRequired()
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<int>("SurveyId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SurveyId");
+
+                    b.ToTable("SurveyQuestions");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SurveyResponse", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<int>("SurveyId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SurveyId");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("SurveyResponses");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Tenant", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(50)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Name")
+                        .IsUnique();
+
+                    b.ToTable("Tenants");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.User", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Email")
+                        .IsRequired()
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<string>("FirstName")
+                        .IsRequired()
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<string>("LastName")
+                        .IsRequired()
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<string>("Password")
+                        .IsRequired()
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<int?>("ProfessorId")
+                        .HasColumnType("integer");
+
+                    b.Property<int?>("StudentId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("TenantId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("UserTypeId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Username")
+                        .IsRequired()
+                        .HasColumnType("character varying(50)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ProfessorId")
+                        .IsUnique();
+
+                    b.HasIndex("StudentId")
+                        .IsUnique();
+
+                    b.HasIndex("TenantId");
+
+                    b.HasIndex("UserTypeId");
+
+                    b.HasIndex("Username", "TenantId")
+                        .IsUnique();
+
+                    b.ToTable("Users");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.UserType", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(50)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Name")
+                        .IsUnique();
+
+                    b.ToTable("UserTypes");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Communication", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Course", "Course")
+                        .WithMany("Communications")
+                        .HasForeignKey("CourseId");
+
+                    b.HasOne("Tsi1.DataLayer.Entities.Tenant", "Tenant")
+                        .WithMany("Communications")
+                        .HasForeignKey("TenantId");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Connection", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Group", "Group")
+                        .WithMany("Connections")
+                        .HasForeignKey("GroupName");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Course", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Tenant", "Tenant")
+                        .WithMany("Courses")
+                        .HasForeignKey("TenantId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.ForumUser", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Forum", "Forum")
+                        .WithMany("ForumUsers")
+                        .HasForeignKey("ForumId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.User", "User")
+                        .WithMany("ForumUsers")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Post", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Forum", "Forum")
+                        .WithMany("Posts")
+                        .HasForeignKey("ForumId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.User", "User")
+                        .WithMany("Posts")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.PostMessage", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Post", "Post")
+                        .WithMany("PostMessages")
+                        .HasForeignKey("PostId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.User", "User")
+                        .WithMany("PostMessages")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Professor", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Tenant", "Tenant")
+                        .WithMany("Professors")
+                        .HasForeignKey("TenantId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.ProfessorCourse", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Course", "Course")
+                        .WithMany("ProfessorCourses")
+                        .HasForeignKey("CourseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.Professor", "Professor")
+                        .WithMany("ProfessorCourses")
+                        .HasForeignKey("ProfessorId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Section", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Course", "Course")
+                        .WithMany("Sections")
+                        .HasForeignKey("CourseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SectionItem", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.File", "File")
+                        .WithOne("SectionItem")
+                        .HasForeignKey("Tsi1.DataLayer.Entities.SectionItem", "FileId");
+
+                    b.HasOne("Tsi1.DataLayer.Entities.Forum", "Forum")
+                        .WithOne("SectionItem")
+                        .HasForeignKey("Tsi1.DataLayer.Entities.SectionItem", "ForumId");
+
+                    b.HasOne("Tsi1.DataLayer.Entities.Section", "Section")
+                        .WithMany("SectionItems")
+                        .HasForeignKey("SectionId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.SectionItemType", "SectionItemType")
+                        .WithMany("SectionItems")
+                        .HasForeignKey("SectionItemTypeId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.Survey", "Survey")
+                        .WithOne("SectionItem")
+                        .HasForeignKey("Tsi1.DataLayer.Entities.SectionItem", "SurveyId");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Student", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Tenant", "Tenant")
+                        .WithMany("Students")
+                        .HasForeignKey("TenantId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.StudentCourse", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Course", "Course")
+                        .WithMany("StudentCourses")
+                        .HasForeignKey("CourseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.Student", "Student")
+                        .WithMany("StudentCourses")
+                        .HasForeignKey("StudentId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Survey", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Tenant", "Tenant")
+                        .WithMany("Surveys")
+                        .HasForeignKey("TenantId");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SurveyAnswer", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.AnswerOption", "AnswerOption")
+                        .WithMany("SurveyAnswers")
+                        .HasForeignKey("AnswerOptionId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.SurveyQuestion", "SurveyQuestion")
+                        .WithMany("SurveyAnswers")
+                        .HasForeignKey("SurveyQuestionId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.SurveyResponse", "SurveyResponse")
+                        .WithMany("SurveyAnswers")
+                        .HasForeignKey("SurveyResponseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SurveyQuestion", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Survey", "Survey")
+                        .WithMany("SurveyQuestions")
+                        .HasForeignKey("SurveyId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SurveyResponse", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Survey", "Survey")
+                        .WithMany("SurveyResponses")
+                        .HasForeignKey("SurveyId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.User", "User")
+                        .WithMany("SurveyResponses")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.User", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Professor", "Professor")
+                        .WithOne("User")
+                        .HasForeignKey("Tsi1.DataLayer.Entities.User", "ProfessorId");
+
+                    b.HasOne("Tsi1.DataLayer.Entities.Student", "Student")
+                        .WithOne("User")
+                        .HasForeignKey("Tsi1.DataLayer.Entities.User", "StudentId");
+
+                    b.HasOne("Tsi1.DataLayer.Entities.Tenant", "Tenant")
+                        .WithMany("Users")
+                        .HasForeignKey("TenantId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.UserType", "UserType")
+                        .WithMany()
+                        .HasForeignKey("UserTypeId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}
diff --git a/Tsi1.Api/Tsi1.DataLayer/Migrations/20201115152033_add-communication-entity.cs b/Tsi1.Api/Tsi1.DataLayer/Migrations/20201115152033_add-communication-entity.cs
new file mode 100644
index 0000000000000000000000000000000000000000..1438e56bebbfae694d46d59069d99f595da14e0d
--- /dev/null
+++ b/Tsi1.Api/Tsi1.DataLayer/Migrations/20201115152033_add-communication-entity.cs
@@ -0,0 +1,56 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+
+namespace Tsi1.DataLayer.Migrations
+{
+    public partial class addcommunicationentity : Migration
+    {
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "Communication",
+                columns: table => new
+                {
+                    Id = table.Column<int>(nullable: false)
+                        .Annotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn),
+                    Text = table.Column<string>(nullable: true),
+                    ValidUntil = table.Column<DateTime>(nullable: false),
+                    CourseId = table.Column<int>(nullable: true),
+                    TenantId = table.Column<int>(nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_Communication", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_Communication_Courses_CourseId",
+                        column: x => x.CourseId,
+                        principalTable: "Courses",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Restrict);
+                    table.ForeignKey(
+                        name: "FK_Communication_Tenants_TenantId",
+                        column: x => x.TenantId,
+                        principalTable: "Tenants",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Restrict);
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Communication_CourseId",
+                table: "Communication",
+                column: "CourseId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Communication_TenantId",
+                table: "Communication",
+                column: "TenantId");
+        }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "Communication");
+        }
+    }
+}
diff --git a/Tsi1.Api/Tsi1.DataLayer/Migrations/20201115153258_add-column-to-communication.Designer.cs b/Tsi1.Api/Tsi1.DataLayer/Migrations/20201115153258_add-column-to-communication.Designer.cs
new file mode 100644
index 0000000000000000000000000000000000000000..b0d77bab506f06c882acbe8d37f352480e7389af
--- /dev/null
+++ b/Tsi1.Api/Tsi1.DataLayer/Migrations/20201115153258_add-column-to-communication.Designer.cs
@@ -0,0 +1,832 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+using Tsi1.DataLayer;
+
+namespace Tsi1.DataLayer.Migrations
+{
+    [DbContext(typeof(Tsi1Context))]
+    [Migration("20201115153258_add-column-to-communication")]
+    partial class addcolumntocommunication
+    {
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn)
+                .HasAnnotation("ProductVersion", "3.1.4")
+                .HasAnnotation("Relational:MaxIdentifierLength", 63);
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.AnswerOption", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(100)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Name");
+
+                    b.ToTable("AnswerOptions");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Communication", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<int?>("CourseId")
+                        .HasColumnType("integer");
+
+                    b.Property<bool>("IsGlobal")
+                        .HasColumnType("boolean");
+
+                    b.Property<int?>("TenantId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Text")
+                        .IsRequired()
+                        .HasColumnType("character varying(1000)");
+
+                    b.Property<DateTime>("ValidUntil")
+                        .HasColumnType("timestamp without time zone");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CourseId");
+
+                    b.HasIndex("TenantId");
+
+                    b.HasIndex("ValidUntil");
+
+                    b.ToTable("Communications");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Connection", b =>
+                {
+                    b.Property<string>("ConnectionId")
+                        .HasColumnType("text");
+
+                    b.Property<string>("GroupName")
+                        .HasColumnType("text");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("ConnectionId");
+
+                    b.HasIndex("GroupName");
+
+                    b.ToTable("Connections");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Course", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<bool>("IsTemplate")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<int>("TenantId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TenantId");
+
+                    b.HasIndex("Name", "TenantId")
+                        .IsUnique();
+
+                    b.ToTable("Courses");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.File", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<string>("Path")
+                        .IsRequired()
+                        .HasColumnType("character varying(1000)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Path")
+                        .IsUnique();
+
+                    b.ToTable("Files");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Forum", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(50)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Forums");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.ForumUser", b =>
+                {
+                    b.Property<int>("ForumId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("ForumId", "UserId");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("ForumUsers");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Group", b =>
+                {
+                    b.Property<string>("Name")
+                        .HasColumnType("text");
+
+                    b.HasKey("Name");
+
+                    b.ToTable("Groups");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Post", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<DateTime>("Date")
+                        .HasColumnType("timestamp without time zone");
+
+                    b.Property<int>("ForumId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Title")
+                        .IsRequired()
+                        .HasColumnType("character varying(100)");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId");
+
+                    b.HasIndex("ForumId", "Title")
+                        .IsUnique();
+
+                    b.ToTable("Posts");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.PostMessage", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Content")
+                        .IsRequired()
+                        .HasColumnType("character varying(10485760)");
+
+                    b.Property<DateTime>("Date")
+                        .HasColumnType("timestamp without time zone");
+
+                    b.Property<int>("PostId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("PostId");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("PostMessages");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Professor", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("IdentityCard")
+                        .IsRequired()
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<int>("TenantId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TenantId");
+
+                    b.HasIndex("IdentityCard", "TenantId")
+                        .IsUnique();
+
+                    b.ToTable("Professors");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.ProfessorCourse", b =>
+                {
+                    b.Property<int>("ProfessorId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("CourseId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("ProfessorId", "CourseId");
+
+                    b.HasIndex("CourseId");
+
+                    b.ToTable("ProfessorCourses");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Section", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<int>("CourseId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<int>("Order")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CourseId");
+
+                    b.ToTable("Sections");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SectionItem", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<int?>("FileId")
+                        .HasColumnType("integer");
+
+                    b.Property<int?>("ForumId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("Order")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("SectionId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("SectionItemTypeId")
+                        .HasColumnType("integer");
+
+                    b.Property<int?>("SurveyId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("FileId")
+                        .IsUnique();
+
+                    b.HasIndex("ForumId")
+                        .IsUnique();
+
+                    b.HasIndex("SectionId");
+
+                    b.HasIndex("SectionItemTypeId");
+
+                    b.HasIndex("SurveyId")
+                        .IsUnique();
+
+                    b.ToTable("SectionItems");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SectionItemType", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(100)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("SectionItemTypes");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Student", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<int>("Age")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("IdentityCard")
+                        .IsRequired()
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<int>("TenantId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TenantId");
+
+                    b.HasIndex("IdentityCard", "TenantId")
+                        .IsUnique();
+
+                    b.ToTable("Students");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.StudentCourse", b =>
+                {
+                    b.Property<int>("StudentId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("CourseId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("StudentId", "CourseId");
+
+                    b.HasIndex("CourseId");
+
+                    b.ToTable("StudentCourses");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Survey", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<bool>("IsGlobal")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<int?>("TenantId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Name");
+
+                    b.HasIndex("TenantId");
+
+                    b.ToTable("Surveys");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SurveyAnswer", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<int>("AnswerOptionId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("SurveyQuestionId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("SurveyResponseId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("AnswerOptionId");
+
+                    b.HasIndex("SurveyQuestionId");
+
+                    b.HasIndex("SurveyResponseId");
+
+                    b.ToTable("SurveyAnswers");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SurveyQuestion", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Question")
+                        .IsRequired()
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<int>("SurveyId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SurveyId");
+
+                    b.ToTable("SurveyQuestions");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SurveyResponse", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<int>("SurveyId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SurveyId");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("SurveyResponses");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Tenant", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(50)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Name")
+                        .IsUnique();
+
+                    b.ToTable("Tenants");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.User", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Email")
+                        .IsRequired()
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<string>("FirstName")
+                        .IsRequired()
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<string>("LastName")
+                        .IsRequired()
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<string>("Password")
+                        .IsRequired()
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<int?>("ProfessorId")
+                        .HasColumnType("integer");
+
+                    b.Property<int?>("StudentId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("TenantId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("UserTypeId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Username")
+                        .IsRequired()
+                        .HasColumnType("character varying(50)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ProfessorId")
+                        .IsUnique();
+
+                    b.HasIndex("StudentId")
+                        .IsUnique();
+
+                    b.HasIndex("TenantId");
+
+                    b.HasIndex("UserTypeId");
+
+                    b.HasIndex("Username", "TenantId")
+                        .IsUnique();
+
+                    b.ToTable("Users");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.UserType", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("character varying(50)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Name")
+                        .IsUnique();
+
+                    b.ToTable("UserTypes");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Communication", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Course", "Course")
+                        .WithMany("Communications")
+                        .HasForeignKey("CourseId");
+
+                    b.HasOne("Tsi1.DataLayer.Entities.Tenant", "Tenant")
+                        .WithMany("Communications")
+                        .HasForeignKey("TenantId");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Connection", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Group", "Group")
+                        .WithMany("Connections")
+                        .HasForeignKey("GroupName");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Course", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Tenant", "Tenant")
+                        .WithMany("Courses")
+                        .HasForeignKey("TenantId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.ForumUser", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Forum", "Forum")
+                        .WithMany("ForumUsers")
+                        .HasForeignKey("ForumId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.User", "User")
+                        .WithMany("ForumUsers")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Post", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Forum", "Forum")
+                        .WithMany("Posts")
+                        .HasForeignKey("ForumId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.User", "User")
+                        .WithMany("Posts")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.PostMessage", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Post", "Post")
+                        .WithMany("PostMessages")
+                        .HasForeignKey("PostId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.User", "User")
+                        .WithMany("PostMessages")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Professor", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Tenant", "Tenant")
+                        .WithMany("Professors")
+                        .HasForeignKey("TenantId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.ProfessorCourse", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Course", "Course")
+                        .WithMany("ProfessorCourses")
+                        .HasForeignKey("CourseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.Professor", "Professor")
+                        .WithMany("ProfessorCourses")
+                        .HasForeignKey("ProfessorId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Section", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Course", "Course")
+                        .WithMany("Sections")
+                        .HasForeignKey("CourseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SectionItem", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.File", "File")
+                        .WithOne("SectionItem")
+                        .HasForeignKey("Tsi1.DataLayer.Entities.SectionItem", "FileId");
+
+                    b.HasOne("Tsi1.DataLayer.Entities.Forum", "Forum")
+                        .WithOne("SectionItem")
+                        .HasForeignKey("Tsi1.DataLayer.Entities.SectionItem", "ForumId");
+
+                    b.HasOne("Tsi1.DataLayer.Entities.Section", "Section")
+                        .WithMany("SectionItems")
+                        .HasForeignKey("SectionId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.SectionItemType", "SectionItemType")
+                        .WithMany("SectionItems")
+                        .HasForeignKey("SectionItemTypeId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.Survey", "Survey")
+                        .WithOne("SectionItem")
+                        .HasForeignKey("Tsi1.DataLayer.Entities.SectionItem", "SurveyId");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Student", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Tenant", "Tenant")
+                        .WithMany("Students")
+                        .HasForeignKey("TenantId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.StudentCourse", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Course", "Course")
+                        .WithMany("StudentCourses")
+                        .HasForeignKey("CourseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.Student", "Student")
+                        .WithMany("StudentCourses")
+                        .HasForeignKey("StudentId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Survey", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Tenant", "Tenant")
+                        .WithMany("Surveys")
+                        .HasForeignKey("TenantId");
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SurveyAnswer", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.AnswerOption", "AnswerOption")
+                        .WithMany("SurveyAnswers")
+                        .HasForeignKey("AnswerOptionId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.SurveyQuestion", "SurveyQuestion")
+                        .WithMany("SurveyAnswers")
+                        .HasForeignKey("SurveyQuestionId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.SurveyResponse", "SurveyResponse")
+                        .WithMany("SurveyAnswers")
+                        .HasForeignKey("SurveyResponseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SurveyQuestion", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Survey", "Survey")
+                        .WithMany("SurveyQuestions")
+                        .HasForeignKey("SurveyId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.SurveyResponse", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Survey", "Survey")
+                        .WithMany("SurveyResponses")
+                        .HasForeignKey("SurveyId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.User", "User")
+                        .WithMany("SurveyResponses")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.User", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Professor", "Professor")
+                        .WithOne("User")
+                        .HasForeignKey("Tsi1.DataLayer.Entities.User", "ProfessorId");
+
+                    b.HasOne("Tsi1.DataLayer.Entities.Student", "Student")
+                        .WithOne("User")
+                        .HasForeignKey("Tsi1.DataLayer.Entities.User", "StudentId");
+
+                    b.HasOne("Tsi1.DataLayer.Entities.Tenant", "Tenant")
+                        .WithMany("Users")
+                        .HasForeignKey("TenantId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Tsi1.DataLayer.Entities.UserType", "UserType")
+                        .WithMany()
+                        .HasForeignKey("UserTypeId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}
diff --git a/Tsi1.Api/Tsi1.DataLayer/Migrations/20201115153258_add-column-to-communication.cs b/Tsi1.Api/Tsi1.DataLayer/Migrations/20201115153258_add-column-to-communication.cs
new file mode 100644
index 0000000000000000000000000000000000000000..aefb4cf825e18995395e1c5cc472b64a270959fa
--- /dev/null
+++ b/Tsi1.Api/Tsi1.DataLayer/Migrations/20201115153258_add-column-to-communication.cs
@@ -0,0 +1,143 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+namespace Tsi1.DataLayer.Migrations
+{
+    public partial class addcolumntocommunication : Migration
+    {
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropForeignKey(
+                name: "FK_Communication_Courses_CourseId",
+                table: "Communication");
+
+            migrationBuilder.DropForeignKey(
+                name: "FK_Communication_Tenants_TenantId",
+                table: "Communication");
+
+            migrationBuilder.DropPrimaryKey(
+                name: "PK_Communication",
+                table: "Communication");
+
+            migrationBuilder.RenameTable(
+                name: "Communication",
+                newName: "Communications");
+
+            migrationBuilder.RenameIndex(
+                name: "IX_Communication_TenantId",
+                table: "Communications",
+                newName: "IX_Communications_TenantId");
+
+            migrationBuilder.RenameIndex(
+                name: "IX_Communication_CourseId",
+                table: "Communications",
+                newName: "IX_Communications_CourseId");
+
+            migrationBuilder.AlterColumn<string>(
+                name: "Text",
+                table: "Communications",
+                type: "character varying(1000)",
+                nullable: false,
+                oldClrType: typeof(string),
+                oldType: "text",
+                oldNullable: true);
+
+            migrationBuilder.AddColumn<bool>(
+                name: "IsGlobal",
+                table: "Communications",
+                nullable: false,
+                defaultValue: false);
+
+            migrationBuilder.AddPrimaryKey(
+                name: "PK_Communications",
+                table: "Communications",
+                column: "Id");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Communications_ValidUntil",
+                table: "Communications",
+                column: "ValidUntil");
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_Communications_Courses_CourseId",
+                table: "Communications",
+                column: "CourseId",
+                principalTable: "Courses",
+                principalColumn: "Id",
+                onDelete: ReferentialAction.Restrict);
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_Communications_Tenants_TenantId",
+                table: "Communications",
+                column: "TenantId",
+                principalTable: "Tenants",
+                principalColumn: "Id",
+                onDelete: ReferentialAction.Restrict);
+        }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropForeignKey(
+                name: "FK_Communications_Courses_CourseId",
+                table: "Communications");
+
+            migrationBuilder.DropForeignKey(
+                name: "FK_Communications_Tenants_TenantId",
+                table: "Communications");
+
+            migrationBuilder.DropPrimaryKey(
+                name: "PK_Communications",
+                table: "Communications");
+
+            migrationBuilder.DropIndex(
+                name: "IX_Communications_ValidUntil",
+                table: "Communications");
+
+            migrationBuilder.DropColumn(
+                name: "IsGlobal",
+                table: "Communications");
+
+            migrationBuilder.RenameTable(
+                name: "Communications",
+                newName: "Communication");
+
+            migrationBuilder.RenameIndex(
+                name: "IX_Communications_TenantId",
+                table: "Communication",
+                newName: "IX_Communication_TenantId");
+
+            migrationBuilder.RenameIndex(
+                name: "IX_Communications_CourseId",
+                table: "Communication",
+                newName: "IX_Communication_CourseId");
+
+            migrationBuilder.AlterColumn<string>(
+                name: "Text",
+                table: "Communication",
+                type: "text",
+                nullable: true,
+                oldClrType: typeof(string),
+                oldType: "character varying(1000)");
+
+            migrationBuilder.AddPrimaryKey(
+                name: "PK_Communication",
+                table: "Communication",
+                column: "Id");
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_Communication_Courses_CourseId",
+                table: "Communication",
+                column: "CourseId",
+                principalTable: "Courses",
+                principalColumn: "Id",
+                onDelete: ReferentialAction.Restrict);
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_Communication_Tenants_TenantId",
+                table: "Communication",
+                column: "TenantId",
+                principalTable: "Tenants",
+                principalColumn: "Id",
+                onDelete: ReferentialAction.Restrict);
+        }
+    }
+}
diff --git a/Tsi1.Api/Tsi1.DataLayer/Migrations/Tsi1ContextModelSnapshot.cs b/Tsi1.Api/Tsi1.DataLayer/Migrations/Tsi1ContextModelSnapshot.cs
index eb633f950cb0dd895b448ec7f43fc6fdde3db67f..58d7225c9f4c36aae6f9178010638a5c4ec352b0 100644
--- a/Tsi1.Api/Tsi1.DataLayer/Migrations/Tsi1ContextModelSnapshot.cs
+++ b/Tsi1.Api/Tsi1.DataLayer/Migrations/Tsi1ContextModelSnapshot.cs
@@ -37,6 +37,40 @@ namespace Tsi1.DataLayer.Migrations
                     b.ToTable("AnswerOptions");
                 });
 
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Communication", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn);
+
+                    b.Property<int?>("CourseId")
+                        .HasColumnType("integer");
+
+                    b.Property<bool>("IsGlobal")
+                        .HasColumnType("boolean");
+
+                    b.Property<int?>("TenantId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Text")
+                        .IsRequired()
+                        .HasColumnType("character varying(1000)");
+
+                    b.Property<DateTime>("ValidUntil")
+                        .HasColumnType("timestamp without time zone");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CourseId");
+
+                    b.HasIndex("TenantId");
+
+                    b.HasIndex("ValidUntil");
+
+                    b.ToTable("Communications");
+                });
+
             modelBuilder.Entity("Tsi1.DataLayer.Entities.Connection", b =>
                 {
                     b.Property<string>("ConnectionId")
@@ -560,6 +594,17 @@ namespace Tsi1.DataLayer.Migrations
                     b.ToTable("UserTypes");
                 });
 
+            modelBuilder.Entity("Tsi1.DataLayer.Entities.Communication", b =>
+                {
+                    b.HasOne("Tsi1.DataLayer.Entities.Course", "Course")
+                        .WithMany("Communications")
+                        .HasForeignKey("CourseId");
+
+                    b.HasOne("Tsi1.DataLayer.Entities.Tenant", "Tenant")
+                        .WithMany("Communications")
+                        .HasForeignKey("TenantId");
+                });
+
             modelBuilder.Entity("Tsi1.DataLayer.Entities.Connection", b =>
                 {
                     b.HasOne("Tsi1.DataLayer.Entities.Group", "Group")
diff --git a/Tsi1.Api/Tsi1.DataLayer/Tsi1Context.cs b/Tsi1.Api/Tsi1.DataLayer/Tsi1Context.cs
index 468e7dd1b6849216aedf0fee5ad9ae03bffd44b9..b35e7b2f0949cb8086fb134fe60f1d66e79e658b 100644
--- a/Tsi1.Api/Tsi1.DataLayer/Tsi1Context.cs
+++ b/Tsi1.Api/Tsi1.DataLayer/Tsi1Context.cs
@@ -33,6 +33,8 @@ namespace Tsi1.DataLayer
         public DbSet<SurveyResponse> SurveyResponses { get; set; }
         public DbSet<AnswerOption> AnswerOptions { get; set; }
 
+        public DbSet<Communication> Communications { get; set; }
+
 
 
         public Tsi1Context(DbContextOptions options) : base(options) { }
@@ -62,6 +64,7 @@ namespace Tsi1.DataLayer
             modelBuilder.ApplyConfiguration(new SurveyQuestionConfiguration());
             modelBuilder.ApplyConfiguration(new SurveyResponseConfiguration());
             modelBuilder.ApplyConfiguration(new AnswerOptionConfiguration());
+            modelBuilder.ApplyConfiguration(new CommunicationConfiguration());
         }
     }
 }