Django 1.4 Modifying Custom Account Model for Uniqueness of E-mail Addresses
# additional model to incorporate our custom fields to the auth user model
class Account(models.Model):
    user = models.OneToOneField(User)      #link (pointer) to the users other information in User model
    birthdate = models.DateField(blank = True, ) # True makes this field optional
    gender = models.CharField(max_length = 1, choices = GENDER_CHOICE, null = True, blank = True)

    def __unicode__(self):            # define a unicode for the user to access
        return u'%s %s' % (self.user.first_name, self.user.last_name)   # return first and last name in shell


# custom form to gather information from the user for a new account
class UserRegistration(UserCreationForm):
#class RegistrationForm(forms.ModelForm):
    class Meta:
        model = User
        fields = ("first_name", "last_name", "email", "username", "password1", "password2",)

    # ensures uniqueness of user email addresses when registering
    def clean_email(self):
        print "In custom creation"
        email = self.cleaned_data.get(email = 'email')
        username = self.cleaned_data.get(username = 'username')
        # checks if email address already exists
        if User.objects.filter(email__iexact = self.cleaned_data['email']):
            print "Email exists"
#           if email and User.objects.filter(email__iexact = email).exclude(username=username).exists():
                raise forms.ValidationError(u'Email Address is currently used by another user.')
        return email

def Main(request):
    if request.user.is_authenticated():
        latest_events = Event.objects.all().order_by('-created')[:10] # Returns latest 10 events
        my_events = Event.objects.filter(creator=request.user)[:10]   # Returns up to 10 events created by current User
        my_calendars = Calendar.objects.filter(creator=request.user)  # Returns all calendars created by the user
        authForm = None
        loginForm = None
        headerType = "header.html"
    else:
        latest_events = None
        my_events = None
        my_calendars = None
        headerType = "header_main.html"

        authForm = UserRegistration(request.POST or None)
        print "Creating account UserRegistration" # TESTING PRINT
        print "User email = %s " %(User._meta.get_field('email'))
        if request.method == 'POST':
            if authForm.is_valid():
                newUser = authForm.save(commit=False)
                newUser.save()
                newUser = authenticate(username=request.POST['username'], password=request.POST['password1'])
                login(request, newUser)

                return HttpResponseRedirect('/signup/')
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more code on success redirection
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# custom form to display additional sign up information

class RegistrationForm(UserCreationForm):
#class RegistrationForm(forms.ModelForm):
    class Meta:
        model = User
        fields = ("first_name", "last_name", "email", "username", "password1", "password2",)

    def clean_email(self):
        """ensures uniqueness of user email addresses when registering"""
        email = self.cleaned_data.get('email')