gistfile1.rb

class Users::OmniauthCallbacksController < Devise::OmniauthCallbacksController                                                                                                                                                                                                             
  def facebook                                                                                                                                                                                                                                                                             
    facebook_omniauth = request.env["omniauth.auth"]                                                                                                                                                                                                                                       
                                                                                                                                                                                                                                                                                           
    # user exists with fb connect; sign them in                                                                                                                                                                                                                                            
    if @user = User.find_for_facebook_oauth(facebook_omniauth, current_user)                                                                                                                                                                                                               
    # connect FB with existing account                                                                                                                                                                                                                                                     
    elsif @user = User.where(email: facebook_omniauth.info.email).first                                                                                                                                                                                                                    
      @user.provider = auth.provider                                                                                                                                                                                                                                                       
      @user.uid = auth.uid                                                                                                                                                                                                                                                                 
      @user.save                                                                                                                                                                                                                                                                           
                                                                                                                                                                                                                                                                                           
    # FB account AND account with same email do not exist: create a new account with FB?                                                                                                                                                                                                   
    elsif 1     # person clicks "yes, make a new account with this email"                                                                                                                                                                                                                  
      @user = User.create(name: facebook_omniauth.extra.raw_info.name,                                                                                                                                                                                                                     
                          provider: facebook_omniauth.provider,                                                                                                                                                                                                                            
                          uid: facebook_omniauth.uid,                                                                                                                                                                                                                                      
                          email: facebook_omniauth.info.email,                                                                                                                                                                                                                             
                          invite_code: (0...8).map{65.+(rand(25)).chr}.join,                                                                                                                                                                                                               
                          password: Devise.friendly_token[0,20])                                                                                                                                                                                                                           
      @user.build_fit_profile                                                                                                                                                                                                                                                              
      @user.build_current_shipment                                                                                                                                                                                                                                                         
    else                                                                                                                                                                                                                                                                                   
      flash[:alert] = "Please create an account."                                                                                                                                                                                                                                          
      redirect_to new_registration_path                                                                                                                                                                                                                                                    
    end                                                                                                                                                                                                                                                                                    
                                                                                                                                                                                                                                                                                           
    if @user                                                                                                                                                                                                                                                                               
      sign_in(@user, bypass: true)                                                                                                                                                                                                                                                         
      redirect_to recommendations_path                                                                                                                                                                                                                                                     
    end                                                                                                                                                                                                                                                                                    
  end                                                                                                                                                                                                                                                                                      
end

My version also has this:

  def passthrough
    raise ActionController::RoutingError.new('Not Found')
  end