update airbrake api to 2.4
Merge pull request #360 from errbit/airbrake-2-4

update airbrake api to 2.4
Update Devise in response to posted security bulletin

ref: https://groups.google.com/forum/?fromgroups=#!topic/plataformatec-devise/hj6i26Dvshw
Merge pull request #378 from cheald/master

Update Devise per posted security bulletin
Config must be symlinked before assets:precompile is run
Ignore SECRET_TOKEN absense during assets:precompile

This is necessary because Heroku environment variables
are not available during assets precompile stage.
Merge pull request #381 from khustochka/heroku_assets_precompile

Ignore SECRET_TOKEN absense during assets:precompile
Typo [ci skip]
Update notifier.js from https://raw.github.com/airbrake/airbrake-js/master/dist/notifier.js