title: Django: How to set a hidden field on a generic create view?
body: <p>I'm running Django 1.6.x </p>
  
  <p>To extend my user I've added another model storing the data:</p>
  
  <pre><code>class UserProfile (models.Model):
      user = models.ForeignKey(User)
      height = models.IntegerField(blank=True, null=True)
  </code></pre>
  
  <p>Now I wand to add a view, which is allowing the user to add its own infos there. Started with <code>django.views.generic.edit.CreateView</code>, but want also to provide at least the edit/update one to. </p>
  
  <p>So I've added the import and created a view: </p>
  
  <pre><code>from django.views.generic.edit import CreateView, UpdateView
  # .... 
  class UserProfileCreateView(CreateView):
      model = UserProfile
      fields = ['height']
  </code></pre>
  
  <p>Also I've added the entry inside urls.py:</p>
  
  <pre><code>    url(r'^userprofile/new/$', login_required(UserProfileCreateView.as_view()), name="add_userprofile")
  </code></pre>
  
  <p>But now I'm stuck on the point how to assign the user ID in the correct way. I want to have this field set in background. Any hints?</p>