Update .travis.yml
Update .travis.yml

  * Specifying `sudo: false` enables the new container-based stack
  * Cache bundler so it'll build faster

Also see: http://blog.travis-ci.com/2014-12-17-faster-builds-with-container-based-infrastructure/

yuki24/did_you_mean,Ye-Yong-Chi/did_you_mean,yui-knk/did_you_mean