language: ruby
cache: bundler

rvm:
  - 2.4.2
  - 2.3.5
  - 2.2.8

language: ruby
cache: bundler

rvm:
  - 2.5.0
  - 2.4.3
  - 2.3.6
  - 2.2.9

Update ruby versions in Travis
Update ruby versions in Travis

Add Ruby 2.5 to the build matrix.
