.travis.yml in worker-glass-0.2.2 vs .travis.yml in worker-glass-0.2.3

@@ -1,7 +1,11 @@
 language: ruby
 rvm:
-  - 2.1.7
   - 2.2.3
   - 2.3.0
+  - 2.3.1
+  - 2.3.2
+  - 2.3.3
+  - 2.4.0
+  - 2.4.1
 script:
   - bundle exec rake