use correct url's in devise reset password email
use the path url generator
ensure staging points to the correct server
use background mailer for devise

Relies on sidekiq being available. Also this will change to when we bump rails 4.2+ and sidekiq to 3.2.4+. Currently blocked by Cellect client using prerelease of the Celluloid gem. See details on using deliver_later - https://github.com/mperham/sidekiq/blob/master/Changes.md#326
ensure rails is loaded before sidekiq

https://github.com/mperham/sidekiq/issues/1552
make cellect helpers available in tests
Merge pull request #321 from camallen/devise_mailer

devise mailer