.travis.yml in serviceworker-rails-0.2.0 vs .travis.yml in serviceworker-rails-0.3.0

@@ -1,4 +1,6 @@
 language: ruby
 rvm:
+  - 2.1.8
+  - 2.2.5
   - 2.3.0
 before_install: gem install bundler -v 1.11.2