title: Ruby to_json :methods arguments
body: <p>I am using the <code>to_json</code> method on an object, and trying to get the <code>:methods</code> argument to work. I have a method on my model (Drop) called <code>is_favorited_by_user?</code>. This method takes an argument of the <code>current_user</code>, and then checks to see if the drop is favorited by the user. How can I pass this argument through the <code>to_json</code> method.</p>
  
  <pre><code>render :json =&gt; @drops.to_json(:methods =&gt; :is_favorited_by_user?(current_user))
  </code></pre>