title: Tastypie APIKey authentication
body: <p>How does the Tastypie APIKey authentication work?  I know there is a signal as mentioned in the documentation:</p>
  
  <pre><code>from django.contrib.auth.models import User    
  from django.db import models  
  from tastypie.models import create_api_key 
  
  models.signals.post_save.connect(create_api_key, sender=User)
  </code></pre>
  
  <p>However, when is this called? If I want to give a user their APIkey I know I can find it in the APIKey db that this create_api_key function adds the key into, but where and when do I call this models.signals.post_save function?</p>
  
  <p>Is this just another django model?  I think it is?</p>
  
  <p>Is this called everytime a user account is saved?  </p>