title: How to add fields to UserCreationForm in Django?
body: <p>So I've been working on a Django project and I've hit a dead end. Every time that I try to modify the UserCreationForm to account for Insurance ID and/or provider, I hit an error that says I cannot do this:</p>
  
  <pre><code>Unknown field(s) (Insurance Provider, Insurance ID) specified for User
  </code></pre>
  
  <p>I was wondering if anyone could tell me how to add these Fields to the form without having to override my User class?</p>
  
  <pre><code>''' Form used in patient registration. Extends UserCreationForm '''
  class PatientRegisterForm(UserCreationForm):
      email = EmailField(required = True)
      insurance_id = forms.CharField(required=True, label="Insurance ID")
      insurance_provider = forms.CharField(required=True, label="Insurance Provider")
  
      class Meta:
          model = User
          fields = ("email", "password1", "password2", "Insurance ID", "Insurance Provider")
  
      def clean_password2(self):
          password1 = self.cleaned_data.get("password1")
          password2 = self.cleaned_data.get("password2")
          if password1 and password2 and password1 != password2:
             raise forms.ValidationError(
                 self.error_messages['password_mismatch'],
                 code='password_mismatch',
             )
           return password2
  
      def save(self, commit=True):
          user=super(UserCreationForm, self).save(commit=False)
          user.set_password(self.clean_password2())
          user.insurance_id = self.cleaned_data["insurance_id"]
          user.insurance_provider = self.cleaned_data["insurance_provider"]
          if commit:
              user.save()
          return user
  
  ''' This displays the patient login form. Unique because of insurance numbers '''
  def patient_registration(request):
      if request.POST:
          form = PatientRegisterForm(request.POST)
          if form.is_valid():
              new_user = form.save()
              new_patient = Patient(user = new_user)
              new_patient.save()
              temp= Event(activity= '\n'+new_patient.user.get_full_name()+" has registered as a patient ")
              temp.save()
              return HttpResponseRedirect('/login/') # TODO : Refer them to there home page
          else:
              return HttpResponseRedirect('/login/') # TODO : Ditto ^^^
      else:
          form = PatientRegisterForm()
      return render(request, "main_site/patient_registration.html", {"form":form})
  </code></pre>