title: Django: Exposing model method to admin
body: <p>Example model:</p>
  
  <pre><code>class Contestant(models.Model):
      first_name = models.CharField(max_length=255)
      last_name = models.CharField(max_length=255)
      email = models.EmailField()
      ...
  
      def send_registration_email(self):
          ...
  </code></pre>
  
  <p>I'd like to be able to expose this method to the admin so that managers can login and manually call it.  I'm thinking about trying property attributes but not sure if that's gonna work.  Also is it possible to expose a method like this that takes arguments other than self, possibly related objects from a select or something?</p>