class User(models.Model):
  name = models.CharField()

class Project(models.Model):
  name = models.CharField()

class Role(models.Model):
  name = models.CharField()

class UsersProjects(models.Model):
  user = models.ForeignKey(User)
  project = models.ForeignKey(Project)
  roles = models.ManyToManyField(Role)

projectedit_formset_class = inlineformset_factory(Project, UsersProjects)
project = Project.objects.get(id=2)
projectedit_formset = projectedit_formset_class(instance=project)

<form method="post" action=".">
  {{ projectedit_formset.as_table }}
</form>