A docker compose file to work with two or more MySQL containers

docker-compose.yml

version: '2'
services:

  # Web server
  web:
    build:
      context: ./
      dockerfile: Dockerfile
    ports:
      - "80:80"

  # Database
  mysql:
    image: mysql:5.6
    ports:
      - "3306:3306"
    environment:
      MYSQL_ROOT_PASSWORD: root
      MYSQL_USER: user
      MYSQL_PASSWORD: password
      MYSQL_DATABASE: my_database

  # Test Database
  mysql_test:
    image: mysql:5.6
    ports:
      - "3310:3306"
    expose: [3306]
    environment:
      MYSQL_ROOT_PASSWORD: root
      MYSQL_USER: user
      MYSQL_PASSWORD: password
      MYSQL_DATABASE: my_test_database