Docker compose file for node and mongodb

docker-compose.yml

version: "3"
services:
  app:
    container_name: app
    restart: always
    build: .
    volumes:
        - ./:/app
        - /app/node_modules
    ports:
      - "4000:8080"
    links:
      - mongo
  mongo:
    container_name: mongo
    image: mongo:4.2
    ports:
      - "27017:27017"