error.py

 issues:

ERRORS:
auth.User.groups: (fields.E304) Reverse accessor for 'User.groups' clashes with reverse accessor for 'CustomUser.groups'.
        HINT: Add or change a related_name argument to the definition for 'User.groups' or 'CustomUser.groups'.
auth.User.user_permissions: (fields.E304) Reverse accessor for 'User.user_permissions' clashes with reverse accessor for 'CustomUser.user_permissions'.
        HINT: Add or change a related_name argument to the definition for 'User.user_permissions' or 'CustomUser.user_permissions'.
users.CustomUser.groups: (fields.E304) Reverse accessor for 'CustomUser.groups' clashes with reverse accessor for 'User.groups'.
        HINT: Add or change a related_name argument to the definition for 'CustomUser.groups' or 'User.groups'.
users.CustomUser.user_permissions: (fields.E304) Reverse accessor for 'CustomUser.user_permissions' clashes with reverse accessor for 'User.user_permissions'.
        HINT: Add or change a related_name argument to the definition for 'CustomUser.user_permissions' or 'User.user_permissions'.

forms.py

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

from .models import CustomUser

class CustomUserCreationForm(UserCreationForm):

    class Meta(UserCreationForm.Meta):
        model = CustomUser
        fields = UserCreationForm.Meta.fields + ('age',)

class CustomUserChangeForm(UserChangeForm):

    class Meta:
        model = CustomUser
        fields = UserChangeForm.Meta.fields

models.py

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

# Create your models here.
class CustomUser(AbstractUser):
    age = models.PositiveIntegerField(blank=True, null=True)

views.py

from django.shortcuts import render
from django.views.generic import CreateView
from django.urls import reverse_lazy


from .forms import CustomUserCreationForm

# Create your views here.
class SignUpView(CreateView):
    form_class = CustomUserCreationForm
    success_url = reverse_lazy('login')
    template_name = 'users/signup.html'