Se agregan Dockerfile y docker-compose para el uso de Docker

Dockerfile

+FROM node:12
+WORKDIR /app
+COPY package*.json /app/
+COPY . /app
+RUN npm install
+EXPOSE 8081
+CMD [ "node", "src/index.js" ]

docker-compose.yml

+version: "3"
+services:
+  nosql:
+    restart: always
+    build: .
+    ports:
+      - "8081:8081"
+    links:
+      - mongo
+  mongo:
+    container_name: mongo
+    image: mongo
+    ports:
+      - "27017:27017"

src/database.js

 // CONEXIÓN CON MONGODB
 const mongo = require('mongodb');
 // Connection URL
-const url = "mongodb://localhost:27017";
+const url = "mongodb://mongo:27017";
 
 // CONEXIÓN CON DYNAMODB
 var AWS = require("aws-sdk");