title: Django - Create a User instance from another model that uses User as a OneToOne
body: <p>I think an example will explain it better.</p>
  
  <p>Lets say I am making an application for various Libraries to show what books they have available. </p>
  
  <p>The site will have Users that are registered through the built-in user registration system and User model. These Users (think of it like library members) can visit the Libraries and browse and checkout the available books.</p>
  
  <p>The site will also allow Libraries to register themselves, and part of that registration is declaring a "Librarian," a person who controls what books are available in their particular Library.</p>
  
  <p>I want to create a Library Registration Form that takes the information of this Library and its Librarian and not only creates an instance of the Library model, but also an instance of the User model. The Librarian automatically becomes a User.</p>
  
  <p>This is my current <strong>models.py</strong>:</p>
  
  <pre><code>    class Library(models.Model):
          name = models.CharField(max_length=200)
          website = models.URLField()
          street = models.CharField(max_length=200)
          city = models.CharField(max_length=200)
          state_or_province = models.CharField(max_length=200)
          postal_code = models.CharField(max_length=200)
          date_registered = models.DateField(auto_now_add=True)
          librarian = models.OneToOneField(User, on_delete=models.CASCADE)
  
      @receiver(post_save, sender=Library)
      def create_user(sender, instance, created, **kwargs):
          if created:
              User.objects.create(user=instance)
          instance.user.save()
  </code></pre>
  
  <p>I am currently lost as to how to build <strong>views.py</strong> and <strong>forms.py</strong>. I am not even sure that model is built correctly, since I need the form to include not only the Library information, but also User information (first_name, last_name, email, password...). Do I need to duplicate that information in the Library model in order for it to pass to the form?</p>
  
  <p>Basically, I don't have a good grasp of how to models connect to one another via Django tools and files. If anyone can point me in the right direction, I would appreciate it. Thanks!</p>