version: '3'
services:
  db:
    image: mysql:5.7
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD: example
      MYSQL_DATABASE: example_db
      MYSQL_USER: example_user
      MYSQL_PASSWORD: example_pass
    volumes:
      - db_data:/var/lib/mysql
    ports:
      - "3306:3306"
volumes:
  db_data: