[1.6.x] Fixed #21560 -- Added missing 'slug' field in example code.
[1.6.x] Fixed #21560 -- Added missing 'slug' field in example code.

Backport of 744aac6dac from master

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