old_contents: from django.conf.urls import url 
  from . import views as blog
  
  urlpatterns = [
      url(r'^category/(?P<slug>[\w-]+)/$', blog.category, name='category'),
      url(r'^category/$', blog.category, name='category'),
      url(r'^(?P<slug>[\w-]+)/$', blog.article, name='article'),
      url(r'^$', blog.home, name='home'),
  ]
  
new_contents: from django.conf.urls import url 
  from . import views as blog
  
  urlpatterns = [
      url(r'^category/(?P<slug>[\w-]+)/$', blog.category, name='category'),
      url(r'^category/$', blog.category, name='category'),
      url(r'^article/(?P<slug>[\w-]+)/$', blog.article, name='article'),
      url(r'^$', blog.home, name='home'),
  ]
  
subject: move all articles to /article subdirectory