title: Django store user image in model
body: <p>I'm trying to create a field in a model, that should store an image for a registered user.
  This image should be renamed and stored in a separate user directory like <code>media/users/10/photo.jpeg</code>.</p>
  
  <p>I've searched a lot, but still can't find how to do it cleanly and correctly. It seems to me that many sites require the same functionality and this should be in django docs, but it is not.</p>