title: Travis CI : The command "bundle exec rake" exited with 1
body: <p>I don't seem to understand the issue, everything works fine locally but when pushed to git travis does not pass it and give error <code>The command "bundle exec rake" exited with 1</code>.
  Here is my PR <a href="https://github.com/shakacode/react-webpack-rails-tutorial/pull/450" rel="nofollow noreferrer">https://github.com/shakacode/react-webpack-rails-tutorial/pull/450</a></p>
  
  <p>And here is the travis CI link <a href="https://travis-ci.org/shakacode/react-webpack-rails-tutorial/builds/448461518?utm_source=github_status&amp;utm_medium=notification" rel="nofollow noreferrer">https://travis-ci.org/shakacode/react-webpack-rails-tutorial/builds/448461518?utm_source=github_status&amp;utm_medium=notification</a></p>