django registration form does not save information - django

Question

I am new to django . here I want to register user and I have a problem whenever the user hit signup button in registration.html nothing happens and when I go to the admin section no user saved so here are my codes
note : all functions and templates works as expected , I think the problem in
UserFormView or urls.py
views.py :
from django.http import Http404
from .models import Category, Item , Order
from django.shortcuts import render, redirect
from django.core.urlresolvers import reverse_lazy
from django.contrib.auth import authenticate , login
from django.views import generic
from django.views.generic import View
from .forms import UsrForm
class IndexView(generic.ListView) :
template_name = 'res/home.html'
context_object_name = 'all_categories'
def get_queryset(self):
return Category.objects.all()
def detail(request, category_name):
try:
category = Category.objects.get(category_title = category_name)
all_categories = Category.objects.all()
items = category.items.all()
except Category.DoesNotExist:
raise Http404("Category does not exist")
return render(request, 'res/menu.html', {'items': items,'all_categories': all_categories})
class UserFormView(View):
form_class = UsrForm
template_name = 'res/registration.html'
def get(self, request):
form = self.form_class(None)
return render(request , self.template_name, {'form' : form})
def post(self, request):
form = self.form_class(request.POST)
if form.is_valid():
user = form.save(commit=False)
username = form.cleaned_data['username']
password = form.cleaned_data['password']
user.set_password(password)
user.save()
user = authenticate(username=username , password=password)
if user is not None:
if user.is_active:
login(request , user)
return redirect('res')
return render(request, self.template_name, {'form': form})
urls.py :
from django.conf.urls import url
from . import views
urlpatterns = [
url(r'^$', views.IndexView.as_view() , name='menu'),
url(r'^register/$', views.UserFormView.as_view() , name='register'),
url(r'^(?P<category_name>[a-z]+)/$', views.detail, name='detail'),
]
forms.py :
from django.contrib.auth.models import User
from django import forms
class UsrForm(forms.ModelForm):
password = forms.CharField(widget=forms.PasswordInput)
class Meta:
model = User
fields = ['username' , 'email' , 'password' ]
here is registration.py :
{% extends 'res/base.html' %}
{% block section %}
<h2>Sign up</h2>
<form method="post">
{% csrf_token %}
{% for field in form %}
<p>
{{ field.label_tag }}<br>
{{ field }}
{% if field.help_text %}
<small style="color: grey">{{ field.help_text }}</small>
{% endif %}
{% for error in field.errors %}
<p style="color: red">{{ error }}</p>
{% endfor %}
</p>
{% endfor %}
<button type="submit">Sign up</button>
</form>
{% endblock %}