title: In cancan, how to check if can? manage each and every record for a given model
body: <ol>
  <li>My admin <code>can :manage, Widget</code></li>
  <li>My user <code>can :manage, Widget, :user_id =&gt; user.id</code></li>
  <li>In my view, I want to show a link only if the current_user can manage <em>each and every</em> Widget record.</li>
  </ol>