title: Django 2.0 'name' is not a registered namespace
body: <p>I've seen this error posted several times, but I can't find anyone using Django 2.0 and having the problem. </p>
  
  <p>The problem cropped up when I tried to nest one app inside another. The nested app (called "users") is meant to allow users to login and out. After putting that segment in, I'm getting the following error:</p>
  
  <pre><code>Template error:
  In template C:\Users\arbit\Documents\python\learning_log\learning_logs\templates\learning_logs\base.html, error at line 6
     'users' is not a registered namespace
     1 : &lt;p&gt;
     2 :     &lt;a href="{% url 'learning_logs:index' %}"&gt;Learning Log&lt;/a&gt; 
     3 :     &lt;a href="{% url 'learning_logs:topics' %}"&gt;Topics&lt;/a&gt; 
     4 :     {% if user.is_authenticated %}
     5 :         Hello, {{ user.username }}.
     6 :         &lt;a href=" {% url 'users:logout' %} "&gt;log out&lt;/a&gt;
     7 :     {% else %}
     8 :         &lt;a href="{% url 'users:login' %}"&gt;log in&lt;/a&gt;
     9 :     {% endif %}
     10 : &lt;/p&gt;
     11 : 
     12 : {% block content %}{% endblock content %}
     13 : 
  </code></pre>
  
  <p>Here's my root urls.py</p>
  
  <pre><code>from django.urls import path, include
  from django.contrib import admin
  
  from . import views
  
  app_name = "learning_log"
  
  urlpatterns = [
      path('admin/', admin.site.urls),
      path('users/', include('users.urls')),
      path('', include('learning_logs.urls')),
  ]
  
  urlpatterns = [
      # Home page
      path('', views.index, name='index'),
  
      # Show all topics
      path('topics/', views.topics, name='topics'),
  
      # Detail page for a single topic
      path('topics/&lt;int:topic_id&gt;/', views.topic, name='topic'),
  
      # Page for adding a new topic
      path('new_topic/', views.new_topic, name='new_topic'),
  
      # Page for adding a new entry
      path('new_entry/&lt;int:topic_id&gt;/', views.new_entry, name='new_entry'),
  
      # Page for editing an entry
      path('edit_entry/&lt;int:entry_id&gt;/', views.edit_entry, name='edit_entry'),
  ]
  </code></pre>
  
  <p>... and the app "users" url.py</p>
  
  <pre><code>from django.urls import path
  from django.contrib.auth.views import login
  
  from . import views
  
  app_name = 'users'
  
  urlpatterns = [
      # Login page.
      path('login/', login, {'template_name': 'users/login.html'}, name='login'),
  
      # Logout page
      path('logout/', views.logout_view, name='logout'),
  ]
  </code></pre>
  
  <p>and the base.html from the "users" app</p>
  
  <pre><code>&lt;p&gt;
      &lt;a href="{% url 'learning_logs:index' %}"&gt;Learning Log&lt;/a&gt; 
      &lt;a href="{% url 'learning_logs:topics' %}"&gt;Topics&lt;/a&gt; 
      {% if user.is_authenticated %}
          Hello, {{ user.username }}.
          &lt;a href="{% url 'users:logout' %}"&gt;log out&lt;/a&gt;
      {% else %}
          &lt;a href="{% url 'users:login' %}"&gt;log in&lt;/a&gt;
      {% endif %}
  &lt;/p&gt;
  
  {% block content %}{% endblock content %}
  </code></pre>
  
  <p>I'm admittedly using an older tutorial and thus am sure the problem has to do with something that is in Django 2.0 but not in the older version that the book covers. Your help is greatly appreciated.</p>