django populate db with some data when new user is created

Question

How can I populate the following tables with some default / initial data, every-time new user is created ? I know about this https://docs.djangoproject.com/en/dev/howto/initial-data/, but this works only when I create models. Here I want to insert some default entries when new user is created.

Additionally, when I create a new user how can I add him to a given group with a static group id automatically ?

models.py

from django.db import models
from django.contrib.auth.models import User

class Category(models.Model):
    name = models.CharField(max_length=50)
    user = models.ForeignKey(User)

class Feed(models.Model):
    url = models.URLField()
    name = models.CharField(max_length=50)
    created = models.DateTimeField(auto_now_add=True)
    description = models.TextField(blank=True)
    category = models.ForeignKey(Category)
    user = models.ForeignKey(User)

views.py

def signup(request):
    if request.method == 'POST':
        form = UserCreationForm1(request.POST)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect("/accounts/login")
    else:
        form = UserCreationForm1()
    return render(request, "registration/signup.html", {
        'form': form,

    })

forms.py

class UserCreationForm1(UserCreationForm):
    email = forms.EmailField(required=True)

    class Meta:
        model = User
        fields = ('username', 'email')

Many thanks!

Answer 1

What you're looking for is Django's signals framework.

from django.db.models.signals import post_save
from django.dispatch import receiver

from django.contrib.auth.models import User, Group
from my_app import Category, Feed

@receiver(post_save, sender=User)
def init_new_user(instance, created, raw, **kwargs):
    # raw is set when model is created from loaddata.
    if created and not raw:
        instance.groups.add(
            Group.objects.get(name='new-user-group'))

        Category.objects.create(
            name="Default", user=instance)

        Feed.objects.create(
            user = instance,
            name = "%s's Feed" % instance.first_name,
            ....
        )

REF: https://docs.djangoproject.com/en/1.5/topics/signals/