social-network.rb

# https://github.com/arsduo/koala/wiki
# https://github.com/arsduo/koala/wiki/Test-Users

# routes.rb
match ‘/auth/failure’, :to => ‘profiles#failure’

# profiles_controller.rb
class ProfilesController < ApplicationController
  def failure
    redirect_to login_url, :flash => {:alert => "Could not log you in. #{params[:message]}"}
  end
end

# https://github.com/plataformatec/devise/wiki/OmniAuth:-Testing

# config/omniauth.rb
if Rails.env == "production"
  # no production app yet
else
  if ENV['USER'] == 'monica'
    Rails.application.config.middleware.use OmniAuth::Builder do
      provider :twitter, 'CONSUMER_KEY', 'CONSUMER_SECRET'
      provider :facebook, 'APP_ID', 'APP_SECRET'  # Find these values on the Facebook App page
    end
  end
end

# login page
<%= link_to "Log in with Facebook", "/auth/facebook" %>