Change 'hoptoad_notifier' to 'airbrake'.
Fix issue of failed page to create apps

The page to create an apps failed.

Fix #586
Merge pull request #588 from ugisozols/typo_airbrake

Change 'hoptoad_notifier' to 'airbrake'.
update Changelog [ci skip]
Update Gem like rails 3.2.15
Merge remote-tracking branch 'upstream/master'