id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
24215	Refactor of lazy model operations	Alex Hill	nobody	"I dealt with `add_lazy_relation()` a few months ago working on Mezzanine and I thought it could use some detangling.

Now that the list of pending operations is stored in the Apps class, it makes sense to put the related methods on that class as well. Running a function when a model is loaded seems an appropriate job for the app registry object.

I've introduced a more generic API, whereby a user-supplied function can be called once any number of models are ready, with those freshly-loaded models as its arguments (plus optional kwargs), a helper function for related models, and the old `add_lazy_relation()` reimplemented in terms of the new API with a deprecation warning.

"	Cleanup/optimization	new	Database layer (models, ORM)	1.8alpha1	Normal				Unreviewed	1	0	0	0	0	0