.travis.yml in gon-6.0.1 vs .travis.yml in gon-6.1.0

@@ -1,14 +1,17 @@
 language: ruby
 sudo: false
 rvm:
   - 1.9.3
   - 2.0.0
-  - 2.1.6
-  - 2.2.2
+  - 2.1
+  - 2.2
+  - 2.3.0
+  - ruby-head
   - jruby-19mode # JRuby in 1.9 mode
   - rbx
 matrix:
   allow_failures:
     - rvm: rbx
+    - rvm: ruby-head
 # uncomment this line if your project needs to run something other than `rake`:
 # script: bundle exec rspec spec