[1.7.x] Fixed #23778 -- Added a doc section on using the Django runner for reusable apps.
[1.7.x] Fixed #23778 -- Added a doc section on using the Django runner for reusable apps.

Backport of 06726965c3e53e9a6b87e1532951a93d5f94f426 from master.

jyotsna1820/django,jyotsna1820/django,oscaro/django,oscaro/django,oscaro/django,jyotsna1820/django,jyotsna1820/django,oscaro/django