title: Django Admin Bulk Edit on Many to Many Relationship
body: <p>In my Django app, I have two models: Publications and Tags.  These two models have a many to many relationship:</p>
  
  <pre><code>class Tag(models.Model):
      title = models.CharField(max_length=50,)
  
  class Publication(models.Model):
      title = models.CharField(max_length=200,)
      tags = models.ManyToManyField(Tag, blank=True, related_name="publications", null=True)
  </code></pre>
  
  <p>On the admin site, I'd like to be able to make bulk edits to the publication objects.  Specifically, I'd like to be able to update the tags for a group of publications. </p>
  
  <p>For example, if I choose from the publications page, "publication 1, publication 2, and publication 3," and create an action that says "change_tags" and I hit go, I see the list of tags in the database and I can select from that list and add the chosen tags to all three publications.  </p>
  
  <p>I don't know if there is a way to do this.  I checked the Django docs on adding actions: <a href="https://docs.djangoproject.com/en/dev/ref/contrib/admin/actions/#ref-contrib-admin-actions" rel="nofollow">https://docs.djangoproject.com/en/dev/ref/contrib/admin/actions/#ref-contrib-admin-actions</a> but the example given doesn't address the complexity of what I am trying to do.</p>