title: How can I add a scope just for some actions on ActiveAdmin
body: <p>I have a classic posts-belongs-to-user association. I want to apply a default_scope to all the actions like <code>#index</code> so it lists my posts only. But I want the ability to see posts from anybody when I go to the <code>#show</code> action if follow a link to it.</p>
  
  <p>How can I avoid the default_scope to be applied on that action?</p>
  
  <pre><code>class Post &lt; ActiveRecord::Base
    belongs_to :user
  end
  
  ActiveAdmin.register CertificationModel do
    controller do
      def scoped_collection
        current_user.posts
      end
    end
  end
  </code></pre>