title: Devise before_filter authenticate_admin?
body: <p>I added an admin role to Devise by adding a admin attribute.</p>
  
  <p>Could you tell me if this is the right way to create a before_filter that requires an admin user to be signed:</p>
  
  <p>in any controller:</p>
  
  <pre><code>before_filter :authenticate_admin!
  </code></pre>
  
  <p>in application_controller</p>
  
  <pre><code>protected
    unless current_user.try(:admin?)      
      redirect_to :new_user_session_path      
    end
  </code></pre>