.travis.yml in barbeque_client-0.8.0 vs .travis.yml in barbeque_client-0.8.1

@@ -1,4 +1,16 @@
 language: ruby
+cache: bundler
+branches:
+  only:
+    - master
 rvm:
-  - 2.2.3
-before_install: gem install bundler -v 1.11.2
+  - ruby-head
+  - 2.4.0
+  - 2.3.1
+  - 2.2.5
+  - 2.1.10
+script:
+  - bundle exec rake
+matrix:
+  allow_failures:
+    - rvm: ruby-head