title: Devise with omniauth redirecting to root url and I can't change it
body: <p>when I log in or sign up with facebook, i'm being redirected to my root url. 
  In my omniauthcallbacks controller this is where I think it's happening:</p>
  
  <pre><code>def facebook
    @user = Artist.from_omniauth(request.env["omniauth.auth"])
  
    if @user.persisted?
      sign_in_and_redirect :artist, @user, :event =&gt; :authentication #this will throw if @user is not activated
      set_flash_message(:notice, :success, :kind =&gt; "Facebook") if is_navigational_format?
    else
      session["devise.facebook_data"] = request.env["omniauth.auth"]
      redirect_to new_user_registration_url
    end
  end
  </code></pre>
  
  <p>What do I have to do to redirect it to another route?</p>