django .db.utils.IntegrityError: Ошибка ограничения NOT NULL: new__score_comment.post_id

Question

Я работал над разделом комментариев для публикации и получал django.db.utils.IntegrityError: NOT NULL constraint failed: new__score_comment.post_id

, поэтому я добавил null=True, blank=True к публикации и пользователю в комментарии класса models.py и перешел к разделу добавления комментариев. но теперь, когда я пытаюсь связать пользователей и сообщения с комментарием, я получаю ту же ошибку

Вот Models.py

class Comment(models.Model):
    post = models.ForeignKey(Post, on_delete=models.CASCADE)
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    # reply = models.ForeignKey('Comment', null=True, related_name="replies")
    content = models.TextField(max_length=160)
    timestamp = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return '{}-{}'.format(self.post.title, str(self.user.username))

Вот views.py:

class PostDetailView(DetailView):
    model = Post
    template_name = "post_detail.html"

    def get_context_data(self, *args, **kwargs):
        context = super(PostDetailView, self).get_context_data()
        post = get_object_or_404(Post, slug=self.kwargs['slug'])
        comments = Comment.objects.filter(post=post).order_by('-id')
        total_likes = post.total_likes()
        liked = False
        if post.likes.filter(id=self.request.user.id).exists():
            liked = True

        if self.request.method == 'POST':
            comment_form = CommentForm(self.request.POST or None)
            if comment_form.is_valid():
                content = self.request.POST.get('content')
                comment = Comment.objects.create(
                    post=post, user=request.user, content=content)
                comment.save()
                return HttpResponseRedirect("post_detail.html")
        else:
            comment_form = CommentForm()

        context["total_likes"] = total_likes
        context["liked"] = liked
        context["comments"] = comments
        context["comment_form"] = comment_form
        return context


class PostCommentCreateView(LoginRequiredMixin, CreateView):
    model = Comment
    form_class = CommentForm

    def form_valid(self, form):
        post = get_object_or_404(Post, slug=self.kwargs['slug'])
        form.instance.user = self.request.user
        form.instance.post = post
        return super().form_valid(form)

    def form_invalid(self, form):
        return HttpResponseRedirect(self.get_success_url())

    def get_success_url(self):
        return reverse('score:post-detail', kwargs=dict(slug=self.kwargs['slug']))