title: How to extend the user model in django 1.9?
body: <p>I've been searching around trying to figure this out, I want to add simple things to my <code>Profile</code> model like avatar, contact info, etc. However when following tutorials that I found online on how to do this, I am only met with errors. </p>
  
  <p>This is what my model looks like (tracks/models.py):</p>
  
  <pre><code>from django.db import models
  from django.core.exceptions import ValidationError
  from django.core.files.images import get_image_dimensions
  from django.contrib.auth.models import User
  
  ...
  
  class Profile(models.Model):
  
      def generate_user_folder_avatar(instance, filename):
          return "uploads/users/%s/%s.png" % (instance.user, 'avatar')
  
      user = models.OneToOneField(User)
  
      avatar = models.ImageField(upload_to=generate_user_folder_avatar,validators=[is_square_png])
  
      def create_user_profile(sender, instance, created, **kwargs):
          if created:
              Profile.objects.create(user=instance)
  
      post_save.connect(create_user_profile, sender=User)
  </code></pre>
  
  <p>I've set the <code>AUTH_PROFILE_MODULE = 'tracks.Profile'</code> in settings.py but when I run my server I get this error:</p>
  
  <pre><code>NameError: name 'post_save' is not defined
  </code></pre>
  
  <p>Any idea what I am doing wrong here? I'm using Django 1.9 and Python 3</p>