title: Active Record Autosave In Reverse Direction
body: <p>Using <a href="http://api.rubyonrails.org/classes/ActiveRecord/AutosaveAssociation.html" rel="nofollow">autosave: true</a> on a <code>has_one</code> or <code>has_many</code> association means that when the parent record is saved, its association(s) are saved as well.</p>
  
  <p>But what if I need the parent to be saved whenever (any of) its association(s) are saved?</p>