title: Problems with django-extensions
body: <p>I install django-extensions like that:</p>
  
  <pre><code>git clone git://github.com/django-extensions/django-extensions.git
  cd django-extensions
  python setup.py install
  </code></pre>
  
  <p>Then I go to my project folder and use:</p>
  
  <pre><code>./manage.py graph_models -a -g -o my_project_visualized.png
  </code></pre>
  
  <p>Whats returns: </p>
  
  <pre><code>Unknown command: 'graph_models'
  Type 'manage.py help' for usage.
  </code></pre>
  
  <p>I try "help" - all of that commands I know, but how can I fix the problem with graph_models?</p>