mceachen/closure_tree — pull request #26 by sturgill (2012-10-24 20:08:06+00:00)
Title: Use :pluck

Rails 3.2 introduced the [pluck method](http://api.rubyonrails.org/classes/ActiveRecord/Calculations.html#method-i-pluck). This prevents you from having to load up full AR model instances just to grab the id field.