Change user validations for omniauthed Users
Change user validations for omniauthed Users

Change user validations:
  * Devise validates user emails so it does not need to be validated
    here.
  * Users cannot have the same provider and uid combination as other
    users. However, users do not need to have an omniauth provider and
    the column can be left blank.

robinsonj/P4IdeaX,robinsonj/P4IdeaX