title: How to set default value of an ordering field +1 of the highest value in Django
body: <p>Thanks in Advance. 
  I have created a model in Django, in which it has a title, url and an Ordering Field. Now I have set the default value of that Ordering Field as <code>ZERO</code> . My requirement is this defult value should be changed to the <code>current highest Ordering number + 1</code>.
  Ho can I do that in Admin Inteface?</p>
  
  <pre><code>class FooterLinks(models.Model):
      title = models.CharField(_("Title"), max_length=200, null = True, blank = True)
      link = models.CharField(_("Link"), max_length = 200)
      order = models.IntegerField(_("Sort Order"), default=0)
  </code></pre>