title: post_save in django to update instance immediately
body: <p>I'm trying to immediately update a record after it's saved. This example may seem pointless but imagine we need to use an API after the data is saved to get some extra info and update the record:</p>
  
  <pre><code>def my_handler(sender, instance=False, **kwargs):
      t = Test.objects.filter(id=instance.id)
      t.blah = 'hello'
      t.save()
  
  class Test(models.Model):
      title = models.CharField('title', max_length=200)
      blah = models.CharField('blah', max_length=200)
  
  post_save.connect(my_handler, sender=Test)
  </code></pre>
  
  <p>So the 'extra' field is supposed to be set to 'hello' after each save. Correct? But it's not working.</p>
  
  <p>Any ideas?</p>