Fix bug for stopping timer

作業中ではないチケットをクローズした時にもタイマーが止まってしまってい
た。
Bump up rails version
Merge pull request #283 from kmiyake/iss-254_bump_up_rails_version

Bump up rails version
Merge pull request #284 from kmiyake/fix_bug_for_stopping_workload_when_close_other_issue

Fix bug for stopping timer
Remove crowdworks_url attribute
Merge pull request #286 from kmiyake/fix_bug_for_iss-278

Remove crowdworks_url attribute
Fix bug for indenting
Merge pull request #287 from kmiyake/hotfix

Fix bug for indenting