Store checkbox value in db's new column - react/django - django

Question

I've been trying to store value of one checkbox, promo_consent, sent from a form into a new column that I've just created in the DB.
Whatever I do it stores always TRUE no matter wheter the checkboxed was checked or not, or stores always FALSE no matter wheter the checkboxes was checked or not.
I have this model:
class User(AbstractBaseUser, PermissionsMixin, PagePermissionMixin):
"""User model for both staff and clients.
It consists of base AbstractBaseUser class and has 2 permissions mixins.
One of them is for standard django permissions and the second is
for Page object permissions.
Note:
This model is used for OAuth2 and Django authentication.
"""
first_name = models.CharField(_('first name'), max_length=30, blank=True)
last_name = models.CharField(_('last name'), max_length=30, blank=True)
email = models.EmailField(_('email address'), unique=True, blank=True)
new_email = models.EmailField(_('new email'), blank=True)
is_staff = models.BooleanField(
_('staff status'),
default=False,
help_text=_('Designates whether the user can log into this admin '
'site.'))
is_active = models.BooleanField(
_('active'),
default=True,
help_text=_('Designates whether this user should be treated as '
'active. Unselect this instead of deleting accounts.'))
date_joined = models.DateTimeField(
_('date joined'),
default=timezone.now)
promo_consent = models.BooleanField(
_('Promo consent'),
default=False,
help_text=_('Shows whether user has agreed to be notified about '
'news and promo sales'))
....
....
....
and this serializer:
class RegistrationSerializer(SerializerSchemaMixin, serializers.Serializer,
SerializerValidateMixin,
EmailUniquenessValidationMixin,
PasswordValidationMixin):
"""Registration serializer."""
first_name = serializers.CharField(max_length=30, default='')
last_name = serializers.CharField(max_length=30, default='')
email = serializers.EmailField(required=True)
password = serializers.CharField(max_length=100, required=True)
password2 = serializers.CharField(max_length=100, required=True)
rules = serializers.BooleanField(required=True)
promo_consent = serializers.BooleanField(required=False)
def validate_rules(self, value):
"""Checks if 'rules' is True."""
if not value:
raise serializers.ValidationError(_('Rules has to be checked'))
else:
return value
def promo_consent(self, value):
return true
def validate(self, data):
"""Override serializer.validate()."""
self.validate_passwords_uniformity(data)
return data
def save(self, **kwargs):
"""Register new user and send confirmation email."""
language = kwargs['language']
email = self.validated_data['email']
promo_consent = self.promo_consent
self.instance = User(first_name=self.validated_data['first_name'],
last_name=self.validated_data['last_name'],
email=email,
is_active=False,
email_confirmation=uuid.uuid4().hex)
self.instance.set_password(self.validated_data['password'])
self.instance.save()
self.instance.send_email_confirmation(language, email)
return self.instance
I've been working this the second day. What am I missing here?