title: TypeError: Direct assignment to the forward side of a many-to-many set is prohibited. Use meeting.set() instead. Error with Django m2m fields
body: <p>I am a beginner in Django and I am stuck with the many-to-many relationship. Here I am fetching the google meet data from my Google calendar through the calendar API. I have successfully fetched the data but when I save the participants of the meeting, I get this error:</p>
  <blockquote>
  <p>TypeError: Direct assignment to the forward side of a many-to-many set is prohibited. Use meeting.set() instead.</p>
  </blockquote>
  <p>This is the code with the problem:</p>
  <pre><code>create a partcipant object &amp; save it
    for email in participants_emails:
      participant_obj,created = Participant.objects.create(
                  meeting=meeting_obj, email=participants_emails) 
      print(f'participant {participant_obj} was created==== ',created)
  </code></pre>
  <p>In this code, I have access to all emails of participants in the <code>participants_emails</code>, and I was to save them in the model.</p>
  <p>Here below is the <code>models.py</code>:</p>
  <pre><code>from django.db import models
  from django.contrib.auth.models import User 
  
  class Meeting(models.Model):
      user = models.ForeignKey(User, on_delete=models.CASCADE)
      unique_key = models.CharField(max_length=100, unique=True)
      subject = models.CharField(max_length=400, null=True, blank=True)
      start_at = models.DateTimeField(
          auto_now_add=False, auto_now=False, null=True)
      end_at = models.DateTimeField(
          auto_now_add=False, auto_now=False, null=True)
      feedback_status = models.BooleanField(null=True, default=False)
  
      def __str__(self):
          return self.subject
  
  class Participant(models.Model):
      meeting = models.ManyToManyField(to=Meeting)
      email = models.EmailField(default=None, blank=True, null=True)
  
      def __str__(self):
          return self.email
  
  class Question(models.Model):
      question_type = [
          ('checkbox', 'CheckBox'),
          ('intvalue', 'Integar Value'),
          ('text', 'Text'),
          ('radio', 'Radio Button'),
      ]
      question_label = models.TextField(null=True, blank=True)
      question_type = models.CharField(
          choices=question_type, default='text', max_length=80)
  
      def __str__(self):
          return self.question_label
  
  class UserFeedback(models.Model):
      meeting = models.ForeignKey(Meeting, on_delete=models.CASCADE)
      participant = models.ForeignKey(Participant, on_delete=models.CASCADE)
      question = models.OneToOneField(Question, on_delete=models.CASCADE)
      question_answer = models.CharField(max_length=300, null=True, blank=True)
  
      def __str__(self):
          return str(self.meeting)
  </code></pre>