[1.6.x] Fixed #21094 -- Updated reuseable apps tutorial to use pip for installation.
[1.6.x] Fixed #21094 -- Updated reuseable apps tutorial to use pip for installation.

Thanks ylb415 at gmail.com for the suggestion.

Backport of e4aab1bb8d from master

redhat-openstack/django,felixjimenez/django,dex4er/django,django-nonrel/django,redhat-openstack/django,redhat-openstack/django,dex4er/django,django-nonrel/django,felixjimenez/django,dex4er/django,django-nonrel/django,felixjimenez/django,redhat-openstack/django,django-nonrel/django,felixjimenez/django