CircleCI V2 Rails + Postgres + Headless Chrome + Rubocop + Heroku we currently use @ Lifen

config.yml

version: 2
jobs:
  checkout_code:
    docker:
      - image: circleci/ruby:2.5.1-node-browsers
      - image: circleci/postgres:10.3-alpine
    working_directory: ~/circleci-app
    steps:
      - checkout
      - save_cache:
          key: v1-repo-{{ .Environment.CIRCLE_SHA1 }}
          paths:
            - ~/circleci-app
  bundle_dependencies:
    docker:
      - image: circleci/ruby:2.5.1-node-browsers
      - image: circleci/postgres:10.3-alpine
    working_directory: ~/circleci-app
    steps:
      - restore_cache:
          keys:
            - v1-repo-{{ .Environment.CIRCLE_SHA1 }}
      - restore_cache:
          keys:
            - v1-bundle-{{ checksum "Gemfile.lock" }}
      - run: bundle install --path vendor/bundle
      - save_cache:
          key: v1-bundle-{{ checksum "Gemfile.lock" }}
          paths:
            - ~/circleci-app/vendor/bundle
  lint:
    docker:
      - image: circleci/ruby:2.5.1-node-browsers
        environment:
          RAILS_ENV: test
    working_directory: ~/circleci-app
    steps:
      - restore_cache:
          keys:
            - v1-repo-{{ .Environment.CIRCLE_SHA1 }}
      - restore_cache:
          keys:
            - v1-bundle-{{ checksum "Gemfile.lock" }}
      - run: bundle --path vendor/bundle
      - run: git diff-tree -r --no-commit-id --name-only 'origin/develop..HEAD' | xargs --no-run-if-empty bundle exec rubocop --config .rubocop.yml --force-exclusion --fail-level warn
  test:
    docker:
      - image: circleci/ruby:2.5.1-node-browsers
        environment:
          RAILS_ENV: test
          DATABASE_URL: postgres://postgres@127.0.0.1:5432/db_name
      - image: circleci/postgres:10.3-alpine
        environment:
          POSTGRES_USER: root
          POSTGRES_DB: db_name
    working_directory: ~/circleci-app
    steps:
      - restore_cache:
          keys:
            - v1-repo-{{ .Environment.CIRCLE_SHA1 }}
      - restore_cache:
          keys:
            - v1-bundle-{{ checksum "Gemfile.lock" }}
      - run: bundle --path vendor/bundle
      - run:
          name: Wait for DB
          command: dockerize -wait tcp://localhost:5432 -timeout 1m
      - run: bundle exec rails db:create db:schema:load
      - run: bundle exec rspec --color --require spec_helper --format RspecJunitFormatter --out ~/rspec/rspec.xml spec --format progress
      - store_test_results:
          path: ~/rspec
      - store_artifacts:
          path: coverage
  deploy_master:
    docker:
      - image: circleci/ruby:2.5.1-node-browsers
    steps:
      - checkout
      - run:
          name: Deploy master branch to Heroku
          command: |
            git push https://heroku:$HEROKU_API_KEY@git.heroku.com/app-production.git master:master
  deploy_staging:
    docker:
      - image: circleci/ruby:2.5.1-node-browsers
    steps:
      - checkout
      - run:
          name: Deploy develop branch to Heroku
          command: |
            git push https://heroku:$HEROKU_API_KEY@git.heroku.com/app-staging.git develop:master

workflows:
  version: 2
  main:
    jobs:
      - checkout_code
      - bundle_dependencies:
          requires:
            - checkout_code
      - lint:
          requires:
            - bundle_dependencies
      - test:
          requires:
            - lint
      - deploy_master:
          requires:
            - test
          filters:
            branches:
              only: master
      - deploy_staging:
          requires:
            - test
          filters:
            branches:
              only: develop