version: '3.7' 
 
services: 
 
  app:
    build: app
    environment:  
      - POSTGRES_USER=postgres 
      - POSTGRES_PASSWORD=postgres 
      - POSTGRES_DB=AppDB
      - PGHOST=db 
      - PGPORT=5432 
      - HOST=localhost
      - PORT=4000
    depends_on: 
      - db 
    ports:  
      - "4000:4000" 

  db: 
    image: postgres:12.2 
    restart: always 
    ports: 
    - "5432:5432" 
    environment: 
      POSTGRES_USER: postgres 
      POSTGRES_PASSWORD: postgres 
      POSTGRES_DB: AppDB 
      PGDATA: /data/postgres 
    volumes: 
      - postgres:/data/postgres 
       
networks:
  default:
    ipam:
      driver: default
      config:
      - subnet: 173.31.0.0/17

volumes: 
    postgres: