# Dockerfile
FROM ruby:2.4.1
RUN apt-get update -qq && apt-get install -y build-essential libpq-dev nodejs
RUN mkdir /yourproject
WORKDIR /yourproject
ADD Gemfile /yourproject/Gemfile
ADD Gemfile.lock /yourproject/Gemfile.lock
RUN bundle install

ADD . /yourproject

#docker-compose.yml
version: '2'
services:
  db:
    image: postgres
    environment:
      - POSTGRES_USER=postgres
      - POSTGRES_PASSWORD=
    volumes:
      - ./data:/var/lib/postgresql/data
  web:
    build: .
    command: >
      sh -c "bundle exec rails db:create &&
             bundle exec rails db:migrate &&
             bundle exec rails s -p 3000 -b '0.0.0.0'"
    volumes:
      - .:/yourproject
    ports:
      - "3000:3000"
    depends_on:
      - db
    environment:
      - PGHOST=db
      - PGUSER=postgres