Let's say I have a simple blog app in Django 1.4:

```
class Post(models.Model):
    title = …
    published_on = …
    tags = models.ManyToManyField('Tag')

class Tag(models.Model):
    name = …

```

i.e. a post has many tags. On the Django admin, I get a nice little `<select multi>` if I include `tags` in the `fields` for the `PostAdmin`. Is there an easy way to include the list of the posts (as a simple `<select multi>`) in the `TagAdmin`? I tried putting `fields = ['name', 'posts']` in the `TagAdmin` and got an `ImproperlyConfigured` error. (same result for `post_set`).

I'm alright with Django, so could whip up a proper AdminForm and Admin object, but I'm hoping there a Right Way™ to do it.