old_contents: from django.conf.urls import patterns, include, url
  from django.contrib import admin
  
  urlpatterns = patterns('',
      # Examples:
      # url(r'^$', 'author.views.home', name='home'),
      url(r'^admin/', include(admin.site.urls)),
      url(r'^books/', include('books.urls')),
  )
  
new_contents: from django.conf.urls import patterns, include, url
  from django.contrib import admin
  
  urlpatterns = patterns('',
      # Examples:
      # url(r'^$', 'author.views.home', name='home'),
      url(r'^admin/', include(admin.site.urls)),
      url(r'^books/', include('books.urls')),
      url(r'^accounts/', include('registration.backends.default.urls')),
  )
  
subject: Add registration URLs