I\'ve followed this tutorial (http://railscasts.com/episodes/236-omniauth-part-2) for creating facebook login with OmniAuth and Devise and I get this error: Circular depend
a lot of gems started breaking on rails 4 , all due to the problem of unloadable in controllers. https://github.com/flyerhzm/switch_user/issues/34 https://github.com/thoughtbot/high_voltage/issues/68 https://github.com/thoughtbot/clearance/issues/276 and many more
you should look into errors that which gem is creating the problem. Once you know that: 1) Check the open issues of that gem 2) If that issue exists and fixed , make sure you have that fix or else update the gem. 3)If not you can create an issue and ask them to fix it. 4) If you dont want to wait for their fix , you can form the gem and push a fix for it https://github.com/cashins/email_preview/commit/b34a077a954b98bd086153fae8979ad142667555 all fix are the same(removing unloadable from the specified controller )
Hope it helps.
if nothing helps downgrade your rails version.