Gitlab Ci for Rails with Docker

.gitlab-ci.yml

stages:
  - test
  - build

variables:
  DB_HOST: postgres
  DB_PASS: postgres
  DB_USER: postgres

brakeman:
  stage: test
  image: ruby:2.4.1
  before_script:
    - bundle install
  script:
    - bundle exec brakeman

rubocop:
  stage: test
  image: ruby:2.4.1
  before_script:
    - bundle install
  script:
    - bundle exec rubocop

rspec:
  stage: test
  image: ruby:2.4.1
  services:
    - postgres:latest
  before_script:
    - bundle install
    - rake db:create RAILS_ENV=test
    - rake db:schema:load RAILS_ENV=test
  script:
    - bundle exec rspec

build:
  stage: build
  only:
    - master
  image: docker:latest
  services:
    - docker:dind
  script:
    - docker build .