matrix:
jobs:
  first_job:
    strategy:
      matrix:
        ruby:
          - "2.1.8"
          - "2.3.1"
        gemfile:
          - gemfiles/Gemfile1
          - gemfiles/Gemfile2
        include:
          - ruby: 2.6.3
            gemfile: gemfiles/Gemfile3
  second_job:
    strategy:
      matrix:
        include:
          - ruby: 2.7.1
            gemfile: gemfiles/Gemfile3