version: "3.8"

services:
  web:
    image: nginx:latest
    ports:
      - "80:80"
    volumes:
      - ./html:/usr/share/nginx/html:ro
    depends_on:
      - app
    networks:
      - frontend

  app:
    build: ./app
    environment:
      DATABASE_URL: postgres://user:password@db:5432/mydb
    depends_on:
      - db
    networks:
      - frontend
      - backend

  db:
    image: postgres:13
    volumes:
      - db_data:/var/lib/postgresql/data
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
      POSTGRES_DB: mydb
    networks:
      - backend

networks:
  frontend:
    driver: bridge
  backend:
    driver: bridge

volumes:
  db_data: