Django 如何保存多对多关系？

我几乎是在使用下面的代码（我把代码分了一点），我使用auto complete light加载用户，用户可以插入不同的人名（用户），用逗号分隔。问题是，当我尝试保存时，会出现以下错误

ValueError at /write/
"<Article: test1>" needs to have a value for field "article" before this many-to-many relationship can be used.

forms.py

class ArticleForm(forms.ModelForm):
    people =  forms.CharField(widget=autocomplete_light.TextWidget('UserAutocomplete'))
    class Meta:
        model = Article

views.py

def write(request):
    if request.POST:
        form = ArticleForm(request.POST)
        if form.is_valid():

            content = form.cleaned_data['content']
            user = User.objects.get(username=request.user.username)

            people_str = form.cleaned_data['accompanied']
            people = [x.strip() for x in accompanied_str.split(',')]

            article = Article(
                content = content,
                author = user,
                )
            for username in accompanied:
                user = User.objects.get(username=username)
                article.people.add(user)

            article.save()

            return HttpResponseRedirect('/success/')

---

为了创建关系，您需要双方的ID。新创建的项目还没有id。如果您先保存文章，然后向其中添加人员，它应该可以正常工作

article = Article(
    content = content,
    author = user,
    )

article.save()

article.add(*User.objects.filter(username__in=accompanied))

---

通过在一次抓取中从用户列表中获取所有拥有用户名的用户，添加用户的过程可能会更便宜。

我简直不敢相信这有多愚蠢，我已经在上面呆了3个小时了！谢谢。

article = Article(
    content = content,
    author = user,
    )

article.save()

article.add(*User.objects.filter(username__in=accompanied))