.travis.yml in paid-1.1.4 vs .travis.yml in paid-1.2.0

@@ -3,9 +3,12 @@
 rvm:
   - 1.9.3
   - 2.0.0
   - 2.1
   - 2.2
+  - 2.2.2
+  - 2.3.0
+  - 2.4.0
 
 gemfile:
   - gemfiles/default-with-activesupport.gemfile
   - gemfiles/json.gemfile
   - gemfiles/yajl.gemfile