def add_file(request, article_id):            
    if request.method == 'POST':  
        form = FileForm(request.POST, request.FILES)  
        if form.is_valid():  
            file = form.save(commit=False)  
            article = Article.objects.get(id=article_id)  
            file.article = article  
            file.save()  
            file.title = article.name + ' ' + file.id  
            file.save()  
            redirect_to = 'redirect to url'  
            return HttpResponseRedirect(redirect_to)