better rename the old values otherwise, trouble

db/migrate/20130906081326_rename_system_username.rb

@@ -0,0 +1,9 @@
+class RenameSystemUsername < ActiveRecord::Migration
+  def up
+    execute "update site_settings set name = 'site_contact_username' where name = 'system_username'"
+  end
+
+  def down
+    execute "update site_settings set name = 'system_username' where name = 'site_contact_username'"
+  end
+end