title: Django: HttpResponseRedirect is not defined
body: <p>I finally managed to POST data from a form to a database in django, however when I press the submit button on my form I get the error:</p>
  
  <pre><code>Request Method:     POST
  Request URL:    http://127.0.0.1:8000/post_url/
  Django Version:     1.11.2
  Exception Type:     NameError
  Exception Value:    
  
  name 'HttpResponseRedirect' is not defined
  
  Exception Location:     /home/xxxx/Desktop/123/src/exercises/views.py in post_treasure, line 26
  Python Executable:  /home/xxxx/Desktop/123/bin/python
  </code></pre>
  
  <p>Relevant views.py:</p>
  
  <pre><code>def post_treasure(request):
      form = TreasureForm(request.POST)
      if form.is_valid():
          treasure = Treasure(name = form.cleaned_data['name'],
                              value = form.cleaned_data['value'],
                              material = form.cleaned_data['material'],
                              location = form.cleaned_data['location'],
                              img_url = form.cleaned_data['img_url'])
          treasure.save()
      return HttpResponseRedirect('/numbers/')
  </code></pre>
  
  <p>Relevant urls.py:</p>
  
  <pre><code>urlpatterns = [
      url(r'^post_url/', post_treasure, name='post_treasure'),
      url(r'^admin/', admin.site.urls),
      url(r'^numbers/', numbers, name="numbers"),
      url(r'^about/', about, name="about")
  ]
  </code></pre>
  
  <p>Other note:</p>
  
  <ul>
  <li>The data is successfully posted if I press the back button to view the new updated data passed from the model to the template, or if I use the admin interface to simply view the data</li>
  </ul>