How to add inline link to user in django admin?

Question

Django

Hello!
I registered the m2m connection with the user in the models:

from django.contrib.auth.models import User

class Item(models.Model):

    users = models.ManyToManyField(User, through='Item_in_cart', verbose_name='Заказавшие', related_name='items')

class Item_in_cart(models.Model):

    item = models.ForeignKey(Item, verbose_name='Товар', on_delete=models.CASCADE)
    user = models.ForeignKey(User, verbose_name='Пользователь', on_delete=models.CASCADE)
    amount = models.IntegerField(verbose_name='Количество')

Now I need Item_in_cart to be displayed in the user in the admin panel (it is in the user, it is not suitable for the item. For this I write

from django.contrib.auth.models import User

class ItemInline(admin.TabularInline):
    model = Item_in_cart
    extra = 1

class UserAdmin(admin.ModelAdmin):
    inlines = (ItemInline, )

admin.site.register(User, UserAdmin)

gives an error django.contrib.admin.sites.AlreadyRegistered: The model User is already registered It
seems logical that the user is already registered in the admin panel, but how to enter the necessary one?
Tell me please

Answer 1

admin.site.unregister(User)
admin.site.register(User, UserAdmin)