title: cancan and namespace - how to change`current_user'" to current_profile
body: <p>I have model profile instead of user and when I`m trying to do sth like that :</p>
  
  <pre><code>  &lt;% if can? :update, @article %&gt;
      &lt;%= link_to "Edit", edit_article_path(@article) %&gt; |
    &lt;% end %&gt;
  </code></pre>
  
  <p>I got en error: 
  undefined local variable or method `current_user' for #</p>
  
  <p>I am also using namespace Admin, so I have <a href="http://localhost:3000/admin/profile" rel="nofollow">http://localhost:3000/admin/profile</a> and so on. 
  Can you please tell me how to change defaults settings ? I have tried to put:</p>
  
  <pre><code>  def current_ability
      @current_user ||= Ability.new(current_profile)
    end
  </code></pre>
  
  <p>in application_controller.rb, but still doesnt work.</p>