.travis.yml in mutant-0.7.6 vs .travis.yml in mutant-0.7.7

@@ -5,9 +5,10 @@
   - TRAVIS=true
 rvm:
   - '1.9'
   - '2.0'
   - '2.1'
+  - '2.2'
   - rbx
 matrix:
   allow_failures:
     - rvm: rbx
 notifications: