Dealing with multiple models in a Django CBVs and ModelForms

gistfile1.py

class UserProfile(models.Model):
    user = models.OneToOneField(User)

    avatar = models.ImageField(upload_to='profile_images', blank=True)

    def __unicode__(self):
        return self.user.username


class RegistrationForm(forms.Form):
    username = forms.CharField()
    email = forms.CharField(widget=forms.EmailInput())
    password = forms.CharField(widget=forms.PasswordInput())
    avatar = forms.ImageField(widget=forms.FileInput(), required=False)

    def clean_email(self):
        email = self.cleaned_data['email']

        try:
            User.objects.get(email=email)
            raise forms.ValidationError('Email already exists')
        except User.DoesNotExist:
            pass
        return email

    def clean_username(self):
        username = self.cleaned_data['username']

        try:
            User.objects.get(username=username)
            raise forms.ValidationError('Username already exists')
        except User.DoesNotExist:
            pass
        return username

    def save(self, commit=True):
        if commit:
            import ipdb; ipdb.set_trace()

            new_user = User.objects.create(
                username=self.cleaned_data['username'],
                email=self.cleaned_data['email'],
                password=self.cleaned_data['password'],
            )

            new_user_profile = UserProfile.objects.create(
                user=new_user
            )

            return new_user_profile

        return super(UserProfile, self).save(commit)


class UserRegistration(FormView):
    template_name = "user/registration.html"
    form_class = RegistrationForm
    success_url = reverse_lazy('home')

    def form_valid(self, form):
        form.save()

        return super(UserRegistration, self).form_valid(form)