title: Django annotate groupings by month
body: <p>I have a very basic model:</p>
  
  <pre><code>class Link(models.Model):
      title = models.CharField(max_length=250, null=False)
      user = models.ForeignKey(User)
      url = models.CharField(max_length=250, blank=True, null=True)
      link_count = models.IntegerField(default=0)
      pub_date = models.DateField(auto_now_add=True)
      updated = models.DateTimeField(auto_now=True)
  </code></pre>
  
  <p>I can create a list of all the entries grouped by date using:</p>
  
  <pre><code>Link.objects.values('pub_date').order_by('-pub_date').annotate(dcount=Count('pub_date'))
  </code></pre>
  
  <p>This will naturally group items by day. But what I really want to do is group by month. Is there anyway I can do this using annotate()?</p>
  
  <p>Many thanks,</p>
  
  <p>G</p>