Make sure Brakeman exit on warnings
Merge branch 'master' into make-sure-brakeman-exit-on-warn

* master:
  Fix quality warnings
  Update rails_best_practices, rubocop
  Update config files after Rails upgrade
  Update slim-rails and depended gems
  Update rails in Gemfile to 4.0.4
Merge pull request #136 from fs/make-sure-brakeman-exit-on-warn

Make sure Brakeman exit on warnings