diff --git a/app/models/customer.rb b/app/models/customer.rb
index 7e34d07..0479438 100644
--- a/app/models/customer.rb
+++ b/app/models/customer.rb
@@ -133,7 +133,7 @@ class Customer < ActiveRecord::Base
   
   private
   
-  def background(&block)
+  def self.background(&block)
     Thread.new do
       yield
       ActiveRecord::Base.connection.close