.travis.yml in knife-ec2-0.12.0 vs .travis.yml in knife-ec2-0.13.0

@@ -1,8 +1,14 @@
 language: ruby
+cache: bundler
 sudo: false
 
+# Early warning system to catch if Rubygems breaks something
+before_install:
+  - gem update --system
+  - gem install bundler
+  - rm -f .bundle/config
+
 rvm:
-  - 2.0.0
   - 2.1
   - 2.2
 script: bundle exec rspec --color --format progress