[Answered ]-Passing data using redirect() + frame URL pattern in Django

With your case. I think you should use reverse because of you do not hard code link, use only change name url.py and do not change your code.

  from django.core.urlresolvers import reverse
  def add(request):
        # Do something
        return redirect('register_index')

Howerver with url have parameter.I have a example

urls.py

  url(r'^detail/(?P<pk>\d+)/$', views.show_detail, name='author_detail'),

view.py

 def view_detail(request):
     return HttpResponseRedirect(reverse('author_detail', kwargs={'pk': self.pk}))