title: how to update OneToOneField of django'user
body: <p>I'm using the real django user.<br>
  In my project my user can create multiple warriors.<br>
  When I want to play I have to choose one of it.<br></p>
  
  <p>So here is what my class looks like:</p>
  
  <pre><code>class Warrior:
      nom = models.CharField(max_length=30, unique=True)
      ...
  
  class Profile(models.Model):
      user = models.OneToOneField(User)
      warrior = models.ForeignKey(Warrior)
  </code></pre>
  
  <p>in my view, I want to change the actual warrior I'm playing with:</p>
  
  <pre><code>warrior = get_object_or_404(Warrior, id=id)
  request.user.profile.warrior = warrior
  </code></pre>
  
  <p>But that code doesn't work. I think I have an error somewhere
  .</p>