Support single-table inheritance when no fields are defined on subclasses

[craigds]

The idea is kind of like proxy models (and could be implemented as variation on proxy models I think.)

I explained this in this thread on django-developers

Joins are bad, so it seems logical to support this kind of thing.

I've come across a number of places where I've had to add if self.type == self.TYPE_FOO) logic to methods; it makes sense to handle this in a more OO way.

[julkiewicz]

I think this is a really good idea! And it looks like it could be implemented fairly easily.

[Kronuz]

I added support for this in my fork: Kronuz@e7d70a3