more ruby versions added to travis config

Author: Fivell

.travis.yml

@@ -2,6 +2,8 @@ script: bundle exec rspec spec
 rvm:
   - 1.9.3
   - 2.0.0
+  - 2.1.5
+  - 2.2.0
 before_install:
   - gem update --system
   - gem --version