pythonlearning/chapter_20/learning_log/urls.py

from django.conf.urls import include, url
from django.contrib import admin

urlpatterns = [
    url(r'^admin/', include(admin.site.urls)),
    url(r'^users/', include('users.urls', namespace='users')),
    url(r'', include('learning_logs.urls', namespace='learning_logs')), 
]