Django custom user model & custom admin

admin.py

from django.contrib import admin
from django.contrib.auth import admin as auth_admin
from .models import *
from forms import UserChangeForm, UserCreationForm


class UserAdmin(auth_admin.UserAdmin):
    fieldsets = (
        (None, {'fields': ('email', 'password')}),
        ('Personal info', {'fields': ('first_name', 'last_name', 'twitter', 'photo', 'event')}),
        ('Permissions', {'fields': ('is_active', 'is_staff', 'is_superuser',
                                       'groups', 'user_permissions')}),
        ('Important dates', {'fields': ('last_login', 'date_joined')}),
    )
    limited_fieldsets = (
        (None, {'fields': ('email',)}),
        ('Personal info', {'fields': ('first_name', 'last_name', 'twitter', 'photo')}),
        ('Important dates', {'fields': ('last_login', 'date_joined')}),
    )
    add_fieldsets = (
        (None, {
            'classes': ('wide',),
            'fields': ('email', 'password1', 'password2')}
        ),
    )
    form = UserChangeForm
    add_form = UserCreationForm
    change_password_form = auth_admin.AdminPasswordChangeForm
    list_display = ('email', 'first_name', 'last_name', 'is_superuser')
    list_filter = ('event', 'is_staff', 'is_superuser', 'is_active', 'groups')
    search_fields = ('first_name', 'last_name', 'email')
    ordering = ('email',)
    readonly_fields = ('last_login', 'date_joined',)

forms.py

from django import forms
from django.contrib.auth import forms as auth_forms
from models import User


class UserCreationForm(forms.ModelForm):
    error_messages = {
        'password_mismatch': "The two password fields didn't match.",
    }
    password1 = forms.CharField(label="Password", widget=forms.PasswordInput)
    password2 = forms.CharField(label="Password confirmation", widget=forms.PasswordInput,
                                help_text="Enter the same password as above, for verification.")

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

    def clean_password2(self):
        password1 = self.cleaned_data.get("password1")
        password2 = self.cleaned_data.get("password2")
        if password1 and password2 and password1 != password2:
            raise forms.ValidationError(
                self.error_messages['password_mismatch'],
                code='password_mismatch',
            )
        return password2

    def save(self, commit=True):
        user = super(UserCreationForm, self).save(commit=False)
        user.set_password(self.cleaned_data["password1"])
        if commit:
            user.save()
        return user


class UserChangeForm(forms.ModelForm):
    password = auth_forms.ReadOnlyPasswordHashField(label="Password",
        help_text="Raw passwords are not stored, so there is no way to see "
                  "this user's password, but you can change the password "
                  "using <a href=\"password/\">this form</a>.")

    class Meta:
        model = User
        fields = '__all__'

    def __init__(self, *args, **kwargs):
        super(UserChangeForm, self).__init__(*args, **kwargs)
        f = self.fields.get('user_permissions', None)
        if f is not None:
            f.queryset = f.queryset.select_related('content_type')

    def clean_password(self):
        return self.initial["password"]

models.py

from django.db import models
from django.contrib.auth import models as auth_models


class UserManager(auth_models.BaseUserManager):

    def create_user(self, email, password=None):
        if not email:
            raise ValueError('Users must have an email address')
        user = self.model(email=self.normalize_email(email))
        user.set_password(password)
        user.save(using=self._db)
        return user

    def create_superuser(self, email, password):
        user = self.create_user(email, password=password)
        user.is_superuser = user.is_staff = True
        user.save(using=self._db)
        return user


class User(auth_models.AbstractBaseUser, auth_models.PermissionsMixin):
    email = models.EmailField(unique=True)
    first_name = models.CharField(max_length=30, blank=True)
    last_name = models.CharField(max_length=30, blank=True)
    is_staff = models.BooleanField(default=False)
    is_active = models.BooleanField(default=True)
    date_joined = models.DateTimeField(auto_now_add=True)

    event = models.ForeignKey('Event', null=True, blank=True, related_name='organizers')
    twitter = models.CharField(max_length=50, null=False, blank=True)
    photo = models.ImageField(upload_to='event/organizers/', null=True, blank=True)

    objects = UserManager()

    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = []

    class Meta:
        verbose_name = 'Organizer'
        verbose_name_plural = 'Organizers'
        ordering = ('id', )

    def __unicode__(self):
        return u'{0} ({1})'.format(self.get_full_name(), self.email)

    def get_short_name(self):
        return self.first_name

    def get_full_name(self):
        return u'{0} {1}'.format(self.first_name, self.last_name)