.travis.yml in slack-ruby-client-0.7.3 vs .travis.yml in slack-ruby-client-0.7.4

@@ -21,5 +21,9 @@
     - rvm: jruby-19mode
     - rvm: rbx-2
 
 git:
   submodules: false
+
+before_install:
+  - gem update bundler
+  - gem update --system