Integrate dj-database-url into Django

[Kenneth Reitz]

dj-database-url gives Django developers two main things:

1. the ability to represent their database settings via a string (a-la sqlalchemy); very useful for environmnent variables and 12factor apps.
2. it will automatically use the DATABASE_URL environment variable, if present.

I'm not sure if #2 is appropriate for Django Core (but it would be nice, as Gunicorn supports both PORT and WEB_CONCURRENCY), but I know #1 is perfect. This plan has previously been discussed (at a conference, DjangoCon EU in Zurich, long ago) and approved by JKM, before his role at Heroku, if that is helpful information.

I think this change would vastly improve the usability of Django, and would be an excellent and simple move for the project.

Many thanks for your consideration. <3

--
Kenneth Reitz

P.S. There is no "Settings" component in the issue tracker, that I can find.

[Tim Graham]

It's better to propose something like this on the DevelopersMailingList where it'll receive more feedback.

[Kenneth Reitz]

Thanks! I'll like to this ticket there.

[Tim Graham]

​django-developers discussion

[Tom Forbes]

I've made an initial PR: ​https://github.com/django/django/pull/8562

I copied most of the 'guts' of the library and fixed up all the tests.

I don't think this is anywhere near ready to merge, but I like the idea and I thought I would take the first step and propose one way to integrate the library.

[Tom Forbes]

I've removed the WIP from my branch as I think the implementation is ready to be discussed. I've got all tests to pass and a mechanism for configuring both the caches and the databases via URLs.