Handling user creation errors

Let's improve the signup form to handle some errors.

Checking whether passwords do not match

What happens if password1 doesn't match password2? To handle such an error, we add the following else block in bold in /accounts/views.py:

…
def signupaccount(request):
    if request.method == 'GET':
        return render(request, 'signupaccount.html', 
                       {'form':UserCreationForm})
    else:
        if request.POST['password1'] ==
          request.POST['password2']:
            user = User.objects.create_user(
   ...