sudo: false
language: ruby
rvm:
  - 2.3.1
before_install: gem install bundler -v 1.13.5

sudo: false
language: ruby
rvm:
  - 2.3.5
  - 2.4.2
before_install: gem install bundler -v 1.13.5

Tweak CI target Ruby versions
Tweak CI target Ruby versions
