.travis.yml in immutable-struct-2.2.2 vs .travis.yml in immutable-struct-2.2.3

@@ -4,7 +4,6 @@
 rvm:
   - 1.9.3
   - 2.0.0
   - 2.1.0
   - 2.2.2
-  - rbx-2
   - ruby-head