views.py

def get_category_users(category):
    return User.objects.filter(item_detail__category=category)


def item_upload(request):
    if request.method == 'POST':
        item = ItemUpload(user=request.user)
        form = ItemUploadForm(request.POST,request.FILES, instance=item)   
        if form.is_valid():
            form.save()
 
            return HttpResponseRedirect('/thanks_user/')
    else:
        form = ItemUploadForm()
        print form
        # get the gadget users
        gadget_users = get_category_users(ItemDetail.GADGET)
    return render(request, 'item-upload.html', {'form' :form, 'gadget_users': gadget_users})