title: ActiveRecord Callbacks List
body: <p>I've been going through the rails source for a while now, and I don't think there's a better way of getting the list of <em>all</em> callbacks other than: <code>ActiveRecord::Callbacks::CALLBACKS</code> – which is a constant list.</p>
  
  <p>Meaning if you're using a gem like devise_invitable that adds a new callback called <code>:invitation_accepted</code> with the score <code>:after</code> and <code>:before</code> then <code>ActiveRecord::Callbacks::CALLBACKS</code> will not work.</p>
  
  <p>Do you know of an easy fix, other than opening up rails modules and making sure there's an internal list of call-backs per model class?</p>