Django - Use email as "username" field

admin.py

from django.contrib import admin
from django.contrib.auth.admin import UserAdmin
from django.utils.translation import gettext_lazy as _

from yourprojectname.member.models import User


@admin.register(User)
class EmailUserAdmin(UserAdmin):
    """
    Administration for custom User model.
    """
    fieldsets = (
        (None, {'fields': ('email', 'password')}),
        (_('Personal info'), {'fields': ('first_name', 'last_name')}),
        (_('Permissions'), {'fields': ('is_active', 'is_staff', 'is_superuser',
                                       'groups', 'user_permissions')}),
        (_('Important dates'), {'fields': ('last_login', 'date_joined')}),
    )
    add_fieldsets = (
        (None, {
            'classes': ('wide',),
            'fields': ('email', 'password1', 'password2'),
        }),
    )
    list_display = ('email', 'first_name', 'last_name', 'is_staff')
    search_fields = ('email', 'first_name', 'last_name',)
    ordering = ('email',)

models.py

from django.contrib.auth.models import AbstractUser, UserManager
from django.db import models
from django.utils.translation import gettext_lazy as _


class EmailUserManager(UserManager):
    """
    Custom manager where username field is removed.
    """
    def _create_user(self, email, password, **extra_fields):
        """
        Create and save a user with the given username, email, and password.
        """
        email = self.normalize_email(email)
        user = self.model(email=email, **extra_fields)
        user.set_password(password)
        user.save(using=self._db)
        return user

    def create_user(self, email=None, password=None, **extra_fields):
        extra_fields.setdefault('is_staff', False)
        extra_fields.setdefault('is_superuser', False)
        return self._create_user(email, password, **extra_fields)

    def create_superuser(self, email, password, **extra_fields):
        extra_fields.setdefault('is_staff', True)
        extra_fields.setdefault('is_superuser', True)

        if extra_fields.get('is_staff') is not True:
            raise ValueError('Superuser must have is_staff=True.')
        if extra_fields.get('is_superuser') is not True:
            raise ValueError('Superuser must have is_superuser=True.')

        return self._create_user(email, password, **extra_fields)


class User(AbstractUser):
    """
    Custom User model with "email" as "username".
    """
    email = models.EmailField(_('email address'), unique=True)

    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = list()

    objects = EmailUserManager()

settings.py

# Note: replace "member" by your app name

INSTALLED_APPS = [
    # ...
    'django.contrib.auth',
    # ...
    'yourprojectname.member',
    # ...
]

AUTH_USER_MODEL = 'member.User'