title: Django 1.8 ArrayField append & extend
body: <p>Django 1.8 <a href="https://docs.djangoproject.com/en/dev/ref/contrib/postgres/fields/">will come with new advanced field types including ArrayField</a> these rely on PostgreSQL and are implemented at a DB level.</p>
  
  <p>PostgreSQL's array field <a href="http://www.postgresql.org/docs/9.1/static/functions-array.html">implements an append method</a>.</p>
  
  <p>However I can't find any documentation on appending an item to an <code>ArrayField</code>. This would clearly be very useful as it would allow the field to be updated without transferring its entire contents from the db then back to it.</p>
  
  <p>Is this possible? If not will it be possible in future? Any pointers to docs I've missed would be much appreciated.</p>
  
  <p>To clarify what I'm asking about, this would be great: </p>
  
  <p><strong>Note: this is fantasy code and I assume won't work (I haven't tried)</strong></p>
  
  <pre><code># on model:
  class Post(models.Model):
      tags = ArrayField(models.CharField(max_length=200))
  
  # somewhere else:
  p = Post.objects.create(tags=[str(i) for i in range(10000)])
  p.tags.append('hello')
  </code></pre>
  
  <p>Is there currently any way of doing this without resorting to raw sql?</p>