Multiple HTML option selection not working - django

Question

I am developing a task management system using the django framework where supervisors can log in and assign tasks to multiple users using Django many to many field. When I log in to the admin portal, I can select multiple users at the same time which saves to the database well. But when I use the front end template, I am able to select multiple users but the selected options never get saved in the database and instead the field will be blank when viewing from the database table.
Here is my Model:
from django.contrib.auth.models import User
class Task(models.Model):
task_title = models.CharField(max_length=30, blank=True, null=True)
unit = models.ForeignKey(Unit, blank=True, null=True)
audit_phase_choice = (
('Pre Engagement', 'Pre Engagement'),
('Understanding Entity', 'Understanding Entity'),
('Risk Assessment', 'Risk Assessment'),
('Performing Audit', 'Performing Audit'),
('Report', 'Report'),
)
audit_phase = models.CharField(max_length=30, blank=True, null=True, choices=audit_phase_choice)
assigned_by = models.CharField(max_length=30, blank=True, null=True)
assigned_to = models.ManyToManyField(User, blank=True)
date_assigned = models.DateTimeField(auto_now_add=False, auto_now=False, blank=True, null=True)
status = models.CharField(max_length=30, blank=True, null=True)
completed = models.BooleanField('Task Completed', default=False)
date_completed = models.DateTimeField(auto_now_add=False, auto_now=False, blank=True, null=True)
start_date = models.DateTimeField(auto_now_add=False, auto_now=False, blank=True, null=True)
due_date = models.DateField(auto_now_add=False, auto_now=False, blank=True, null=True)
comment = models.TextField('comments', max_length=3000, default='', blank=True, null=True)
timestamp = models.DateTimeField(auto_now_add=True, auto_now=False, blank=True)
def __unicode__(self):
return self.task_title
def get_absolute_url(self):
return reverse("taskmis:user_task_edit", kwargs={"id": self.id})
Here is the form.py content
class TaskForm(forms.ModelForm):
class Meta:
model = Task
fields = ['task_title',
'unit',
'assigned_to',
'start_date',
'due_date',
'comment']
Here is the view.py content:
def user_task_entry(request):
title = 'Assign Task'
form = TaskForm(request.POST or None)
if form.is_valid():
instance = form.save(commit=False)
instance.assigned_by = request.user
instance.save()
return redirect('taskmis:user_task_list')
context = {
"title": title,
"form": form,
}
return render(request, "task_entry.html",context)

Answer 1

You need to call save_m2m() manually because you set the commit=False when you call the save method
Django Ref
To work around this problem, every time you save a form using
commit=False, Django adds a save_m2m() method to your ModelForm
subclass. After you’ve manually saved the instance produced by the
form, you can invoke save_m2m() to save the many-to-many form data.
For example: