set log to auth2

config/initializers/omniauth.rb

@@ -1,4 +1,5 @@
 OmniAuth.config.add_camelization 'qq', 'QQ'
+OmniAuth.config.logger = Rails.logger
 OmniAuth.config.on_failure = Proc.new { |env|
   OmniAuth::FailureEndpoint.new(env).redirect_to_failure
 }