.travis.yml in serverengine-1.6.1 vs .travis.yml in serverengine-1.6.2

@@ -1,13 +1,19 @@
 language: ruby
 
 rvm:
-  - 2.2
+  - 2.2.4
+  - 2.3.0
+  - ruby-head
 
 branches:
   only:
     - master
 
 script: bundle exec rake spec
 
 before_install:
  - gem update bundler
+
+matrix:
+  allow_failures:
+    - rvm: ruby-head