.travis.yml in lita-4.4.1 vs .travis.yml in lita-4.4.2

@@ -1,9 +1,10 @@
 language: ruby
+cache: bundler
 rvm:
-  - 2.0.0
-  - 2.1.6
-  - 2.2.2
+  - 2.0
+  - 2.1
+  - 2.2
 script: bundle exec rake
 before_install:
   - gem update --system
 services:
   - redis-server