.travis.yml in might-0.5.1 vs .travis.yml in might-0.5.2

@@ -1,7 +1,8 @@
 sudo: false
 language: ruby
 rvm:
+  - 2.1.5
   - 2.2.2
   - 2.2.3
   - ruby-head
 matrix:
   allow_failures: