old_contents: from django.conf.urls import url
  from . import views
  
  urlpatterns = [
      url(r'^$', views.home, name='home'),
      url(r'^c/$', views.home),
      url(r'^c/(?P<pk>[0-9]+)/$', views.home),
  ]
  
new_contents: from django.conf.urls import url
  from . import views
  
  urlpatterns = [
      url(r'^$', views.home, name='home'),
      url(r'^c/$', views.home),
      url(r'^c/(?P<pk>[0-9]+)/$', views.home),
      url(r'^login/$', views.home),
  ]
  
subject: add login route