Implementing "Secure database" issue

docker-compose.yml

@@ -4,13 +4,19 @@ services:
     container_name: mongodb
     ports:
       - "27017:27017"
+    environment:
+      - MONGO_INITDB_ROOT_USERNAME=${MONGO_INITDB_ROOT_USERNAME}
+      - MONGO_INITDB_ROOT_PASSWORD=${MONGO_INITDB_ROOT_PASSWORD}
+      - MONGO_INITDB_DATABASE=todo-app
 
   todo-app:
-    image: todo-app
+    build:
+      context: .
+      dockerfile: Dockerfile
     container_name: todo-app
     ports:
       - "80:3000"
     depends_on:
       - mongodb
     environment:
-      - MONGO_URI=mongodb://mongodb:27017/todo-app
+      - MONGO_URI=${MONGO_URI}

mongodb.js

-const mongoose = require('mongoose');
-require('dotenv').config(); 
+const mongoose = require("mongoose");
+require("dotenv").config();
 
 const connectDB = async () => {
   try {
-    const conn = await mongoose.connect(process.env.MONGO_URI || "mongodb://mongodb:27017/todo-app");
+    const conn = await mongoose.connect(process.env.MONGO_URI, {
+      useNewUrlParser: true,
+      useUnifiedTopology: true,
+    });
     console.log(`MongoDB connected: ${conn.connection.host}`);
   } catch (err) {
     console.error(`Error: ${err.message}`);