version: '2'
services:
  db:
    image: postgres
  web:
    build: .
    command: python manage.py runserver 0.0.0.0:8000
    volumes:
      - .:/code
    ports:
      - "8000:8000"
    depends_on:
      - db

docker run -d --name=test-mysql --env="MYSQL_ROOT_PASSWORD=mypassword" -P mysql

docker inspect d54cf8a0fb98 |grep HostPort

"HostPort": "32777"

web:
  links:
   - db

version: '2'
services:
  web:
    build: .
    depends_on:
      - db
      - redis
  redis:
    image: redis
  db:
    image: postgres

web:
  image: example/my_web_app:latest
  links:
    - db
    - cache

db:
  image: postgres:latest

cache:
  image: redis:latest