如何在用户注册Django时添加新的数据库条目？

# models.py
from django.contrib.auth.models import AbstractUser
from django.db import models

class CustomUser(AbstractUser):
    phone_number = models.CharField(max_length=15, blank=True)

# forms.py
from django import forms
from .models import CustomUser

class RegistrationForm(forms.Form):
    username = forms.CharField(max_length=150)
    email = forms.EmailField()
    password = forms.CharField(widget=forms.PasswordInput)
    phone_number = forms.CharField(max_length=15)

# views.py
from django.shortcuts import render, redirect
from .forms import RegistrationForm
from .models import CustomUser

def register(request):
    if request.method == 'POST':
        form = RegistrationForm(request.POST)
        if form.is_valid():
            username = form.cleaned_data['username']
            email = form.cleaned_data['email']
            password = form.cleaned_data['password']
            phone_number = form.cleaned_data['phone_number']

            user = CustomUser.objects.create_user(username=username, email=email, password=password)
            user.phone_number = phone_number
            user.save()

            return redirect('registration_success')  # 重定向到注册成功页面
    else:
        form = RegistrationForm()

    return render(request, 'registration.html', {'form': form})

# registration.html
<form method="POST" action="{% url 'register' %}">
  {% csrf_token %}
  {{ form.as_p }}
  <button type="submit">注册</button>
</form>