Added Devise

Overview:
* Added all the required gems
* Created an initializer file `omniauth.rb`. Renamed the config file as `0_glitterconfig.rb` so that the config initializer would run before the others.
* Removed the protected attributes gem, as omniauth-openid was conflicting with it. For this same reason, I've changed to the strong parameters syntax all across the application files.
* Added a user settings page where they can edit their profile, and manage the linked authentications

Tests are not included in this commit, I'll send them in next week.

[Link to working demo](http://glittergallery-ropaku.rhcloud.com/)