AssertionError: OneToOneField(True) is invalid. First parameter to ForeignKey must be either a model, a model name, or the string 'self' Django

Я новичок в Django и это мой первый проект. Делаю сайт с регистрацией, но при запуске сервера вылетает данная ошибка. Понятия не имею почему.

Models:

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


class User(AbstractUser):
   username = models.OneToOneField(max_length=18, unique=True, blank=False, to=True, 
   on_delete=True)
password = models.CharField(max_length=30)
password1 = models.CharField(max_length=30)

USERNAME_FIELD = 'username'

Forms:

from django import forms
from django.contrib.auth.forms import UserCreationForm

from .models import *


class RegisterUserForm(UserCreationForm):
    username = forms.CharField(label='Логин', widget=forms.TextInput(attrs={'class': 'form- 
    input'}))
password1 = forms.CharField(label='Пароль', widget=forms.PasswordInput(attrs={'class': 'form- 
    input'}))
password2 = forms.CharField(label='Повтор пароля', widget=forms.PasswordInput(attrs={'class': 
    'form-input'}))

class Meta:
    model = User
    fields = ('username', 'password1', 'password2')
    widgets = {
        'username': forms.TextInput(attrs={'class': "form-input"}),
        'password1': forms.PasswordInput(attrs={'class': "form-input"}),
        'password2': forms.PasswordInput(attrs={'class': "form-input"}),
    }

Views:

from main.forms import RegisterUserForm

class RegisterUser(CreateView):
    form_class = RegisterUserForm
    template_name = 'main/reg.html'
    success_url = reverse_lazy('login')