diff --git a/app/models/user.rb b/app/models/user.rb
index 71418fc9f..b89a2aa88 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -1,5 +1,6 @@
 # Copyright (C) 2012-2013 Zammad Foundation, http://zammad-foundation.org/
 
+require 'sso'
 require 'digest/sha2'
 require 'organization'