title: Ruby on Rails: alias_method_chain, what exactly does it do?
body: <p>I've tried reading through various blog posts that attempt to explain alias_method_chain and the reasons to use it and not use it. In particular, I took heed to:</p>
  
  <p><a href="http://weblog.rubyonrails.org/2006/4/26/new-in-rails-module-alias_method_chain" rel="noreferrer">http://weblog.rubyonrails.org/2006/4/26/new-in-rails-module-alias_method_chain</a></p>
  
  <p>and</p>
  
  <p><a href="http://yehudakatz.com/2009/03/06/alias_method_chain-in-models/" rel="noreferrer">http://yehudakatz.com/2009/03/06/alias_method_chain-in-models/</a></p>
  
  <p>I still do not see any practical use for alias_method_chain. Would anyone be able to explain a few things.</p>
  
  <p>1 - is it still used at all?<br>
  2 - when would you use alias_method_chain and why?</p>