docker-compose-production.yml

version: '2.1'

volumes:
  postgres-data:
    driver: local

services:
  # service configuration for our web server
  web:
  
    # set the build context to the root of the Rails app
    build:
      context: . 
      # build with a different Dockerfile
      dockerfile: config/containers/Dockerfile-nginx
    
    # makes the web container aware of the app container
    links:
      - app
    
    # expose the port we configured Nginx to bind to
    ports:
      - "80:80"
  
  # service configuration for our dockerized Rails app
  app:
  
    # use the Dockerfile next to this file
    build: .
  
    # sources environment variable configuration for our app
    env_file: .env
  
    # rely on the RAILS_ENV value of the host machine
    environment:
      - RAILS_ENV=production
  
    # makes the app container aware of the DB container
    links:
      - db
  
    # expose the port we configured Unicorn to bind to
    expose:
      - "3000"
  
  # service configuration for our database
  
  db:
   
    # use the preferred version of the official Postgres image
    # see https://hub.docker.com/_/postgres/
    image: postgres:9.4.5
  
    # persist the database between containers by storing it in a volume
    volumes:
      - postgres-data:/var/lib/postgresql/data