.travis.yml in mshard-0.5.0 vs .travis.yml in mshard-0.5.1

@@ -1,7 +1,10 @@
 language: ruby
 sudo: false
 rvm:
   - ruby-head
-  - 2.2.2
-  - 2.1.5
-  - 2.0.0
+  - 2.2.5
+  - 2.3.1
+  - 2.4.0
+before_install:
+  - gem update --system
+  - gem install bundler