Crabgrass/Crabgrass-Core — pull request #31 by azul (2013-03-22 11:36:21+00:00)
Title: Faster user upgrade

Different things to speed up the user migration:
* tracked down instantiation of the associations used
* update all gates in a key in one go
* only trigger one callback then and not one per gate
* only trigger callbacks when sth. actually changed