rvm:
  - "2.2"
  - "2.3"
  - "2.4"
  - "head"
notifications:
  email: false

rvm:
  - "2.2"
  - "2.3"
  - "2.4.0"
  - "ruby-head"
notifications:
  email: false

Fix ruby versions for Travis
Fix ruby versions for Travis
