before_install:
  - gem install bundler
language: ruby
rvm:
  - 2.2.5
  - 2.3.1
matrix:
  include:
    - rvm: 1.9.3
      gemfile: gemfiles/ruby_before_2.2.gemfile
    - rvm: 2.0.0
      gemfile: gemfiles/ruby_before_2.2.gemfile
    - rvm: 2.1.8
      gemfile: gemfiles/ruby_before_2.2.gemfile

before_install:
  - gem install bundler
language: ruby
rvm:
  - 2.2
  - 2.3
  - 2.4
  - 2.5
matrix:
  include:
    - rvm: 1.9.3
      gemfile: gemfiles/ruby_before_2.2.gemfile
    - rvm: 2.0.0
      gemfile: gemfiles/ruby_before_2.2.gemfile
    - rvm: 2.1
      gemfile: gemfiles/ruby_before_2.2.gemfile

Test on new Ruby versions
Test on new Ruby versions