title: Django2.1 : Queryset ModelChoice in a ModelForm then save two forms
body: <p>I want the current logged in user to be able to create and save both forms. The second form has a ManyToManyField and ForeignKey relationships as you can see below.</p>
  <p>Currently I have tried to queryset the current user from <code>ChatGroupUser</code> ModelForm.</p>
  <p>With the current codes, as soon as I try to access the page, Django raise the error below:</p>
  <pre><code>__init__() missing 1 required positional argument: 'user'
  </code></pre>
  <p>it says that the error comes from line 88, which is:</p>
  <pre><code>form_user = ChatGroupUserForm() 
  </code></pre>
  <h1>Full Traceback</h1>
  <pre><code>Traceback (most recent call last):
    File &quot;/Users/macadmin/Documents/Django_fun4/Groupixx/lib/python3.7/site-packages/django/core/handlers/exception.py&quot;, line 34, in inner
      response = get_response(request)
    File &quot;/Users/macadmin/Documents/Django_fun4/Groupixx/lib/python3.7/site-packages/django/core/handlers/base.py&quot;, line 126, in _get_response
      response = self.process_exception_by_middleware(e, request)
    File &quot;/Users/macadmin/Documents/Django_fun4/Groupixx/lib/python3.7/site-packages/django/core/handlers/base.py&quot;, line 124, in _get_response
      response = wrapped_callback(request, *callback_args, **callback_kwargs)
    File &quot;/Users/macadmin/Documents/Django_fun4/Groupixx/groupixx/core/views.py&quot;, line 88, in create_group
      form_user = ChatGroupUserForm()
  TypeError: __init__() missing 1 required positional argument: 'user'
  </code></pre>
  <h1>models.py</h1>
  <pre><code>class ChatGroup(models.Model):
      name = models.CharField(max_length=100, blank=True, null=True)
      group_admin = models.ForeignKey(User, on_delete=models.CASCADE, related_name='chat_group_admins')
      is_active = models.BooleanField(default=True, null=True)
      is_current = models.BooleanField(default=False, null=True)
  
  class ChatGroupUser(models.Model):
      user = models.ManyToManyField(User)
      chat_group = models.ForeignKey(ChatGroup, on_delete=models.CASCADE, related_name='chat_group_users')
  </code></pre>
  <h1>forms.py</h1>
  <pre><code>from django.contrib.auth import get_user_model
  
  User = get_user_model()
  
  class ChatGroupForm(forms.ModelForm):
      class Meta:
          model = ChatGroup
          fields = ['name',]
  
  class ChatGroupUserForm(forms.ModelForm):
      class Meta:
          model = ChatGroupUser
          fields = ['user']
  
      def __init__(self, user, *args, **kwargs):
          super(ChatGroupUserForm, self).__init__(*args, **kwargs)
          self.fields['user'].queryset = User.objects.filter(user=user)
  
  </code></pre>
  <h1>views.py</h1>
  <pre><code>def create_group(request):
      if request.method == 'POST':
          form_group = ChatGroupForm(request.POST)
          form_user = ChatGroupUserForm(request.POST)
  
          if form_group.is_valid():
              create_form = form_group.save(commit=False)
              create_form.group_admin = request.user
              create_form.save()
              form_user.save(commit=False)
              form_user.user = user
              form_user.save()
              return redirect('core:group_list')
  
      else:
          form_group = ChatGroupForm()
          form_user = ChatGroupUserForm()
  
      context = {
              'form_group':form_group,
              'form_user': form_user
      }
      return render(request, 'core/create-group.html', context)
  </code></pre>
  <p>I would appreciate any help, I am not sure why django is throwing an error and why i am not able to create and save both forms.</p>