Add Support for many-to-one relationships (and maybe many-to-many?)

[PhilippMDoerner]

As a user, I want to be able to access and edit objects with foreign keys to my own object.

Now how far can that access go? Simple solution for now would be to provide a list of links to objects pointing to this one. This would only be possible for models with foreign-key fields that point to this one. If I do that, it may be nice to also provide hyper-links to the currently selected option, just to be able to jump back and forth.

Slightly more complicated would be to steal from django and work with modals or open up a window to the right apple style. That would likely mean a fairly considerable amount of JS, which I'm not sure I'm a fan of.