.travis.yml in spy-0.2.4 vs .travis.yml in spy-0.2.5

@@ -1,5 +1,11 @@
 language: ruby
 rvm:
-  - "1.9.3"
-  - "2.0.0"
+  - 1.9.3
+  - 2.0.0
   - jruby-19mode
+  - ruby-head
+  - rbx-19mode
+matrix:
+  allow_failures:
+      - rvm: ruby-head
+      - rvm: rbx-19mode