language: ruby
rvm:
  - 2.1
  - 2.2
  - 2.3.0
before_install: gem install bundler

language: ruby
rvm:
  - 2.1.9
  - 2.2.5
  - 2.3.1
  - ruby-head
before_install: gem install bundler
matrix:
  allow_failures:
    - rvm: ruby-head

Update ruby versions testing against
Update ruby versions testing against

Also experimentally test against Ruby HEAD
