language: ruby
before_install:
 - gem update bundler
rvm:
  - 1.9.3
  - 2.0.0
  - 2.1.8
  - 2.2.4
  - 2.3.0

language: ruby
before_install:
 - gem update bundler
rvm:
  - 1.9.3
  - 2.0
  - 2.1
  - 2.2
  - 2.3
  - 2.4
  - 2.5

Update Ruby versions in Travis build matrix.
Update Ruby versions in Travis build matrix.
