title: Django Get ID of the object in save()
body: <p>I have some fixed number let say it is <code>num = 1000</code> Now I have field which need to be sum of the object.id and num. I need this in save() something like below.</p>
  
  <pre><code>def save(self, *args, **kwargs):
      num = 1000
      self.special = self.id + num
      super(MyModel, self).save(*args, **kwargs)
  </code></pre>
  
  <p>But self.id is known after save and field named special is required. How to get self.id?</p>