django.db.utils.IntegrityError: NOT NULL constraint failed: core_profile.user_id

[vital...@gmail.com]

i'm trying to build a customised registration to my site, so i'm using a sign Up with Profile Model that inherits from django User class with "OneToOneField" relation .

i'm having this ERROR after submit a form that i made to let user complete profile information just after SignUp's email confirmation. Look at this diagram :

The above exception was the direct cause of the following exception:

Traceback (most recent call last):

  File "C:\Python36\lib\site-packages\django\core\handlers\exception.py", line 41, in inner

    response = get_response(request)

  File "C:\Python36\lib\site-packages\django\core\handlers\base.py", line 187, in _get_response

    response = self.process_exception_by_middleware(e, request)

  File "C:\Python36\lib\site-packages\django\core\handlers\base.py", line 185, in _get_response

    response = wrapped_callback(request, *callback_args, **callback_kwargs)

  File "C:\Users\admin\Desktop\dev1\mysite\mysite\core\views.py", line 74, in complete_profile

    form.save()

  File "C:\Python36\lib\site-packages\django\forms\models.py", line 451, in save

    self.instance.save()

  File "C:\Python36\lib\site-packages\django\db\models\base.py", line 806, in save

    force_update=force_update, update_fields=update_fields)

  File "C:\Python36\lib\site-packages\django\db\models\base.py", line 836, in save_base

    updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)

  File "C:\Python36\lib\site-packages\django\db\models\base.py", line 922, in _save_table

    result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)

  File "C:\Python36\lib\site-packages\django\db\models\base.py", line 961, in _do_insert

    using=using, raw=raw)

  File "C:\Python36\lib\site-packages\django\db\models\manager.py", line 85, in manager_method

    return getattr(self.get_queryset(), name)(*args, **kwargs)

  File "C:\Python36\lib\site-packages\django\db\models\query.py", line 1060, in _insert

    return query.get_compiler(using=using).execute_sql(return_id)

  File "C:\Python36\lib\site-packages\django\db\models\sql\compiler.py", line 1099, in execute_sql

    cursor.execute(sql, params)

  File "C:\Python36\lib\site-packages\django\db\backends\utils.py", line 80, in execute

    return super(CursorDebugWrapper, self).execute(sql, params)

  File "C:\Python36\lib\site-packages\django\db\backends\utils.py", line 65, in execute

    return self.cursor.execute(sql, params)

  File "C:\Python36\lib\site-packages\django\db\utils.py", line 94, in __exit__

    six.reraise(dj_exc_type, dj_exc_value, traceback)

  File "C:\Python36\lib\site-packages\django\utils\six.py", line 685, in reraise

    raise value.with_traceback(tb)

  File "C:\Python36\lib\site-packages\django\db\backends\utils.py", line 65, in execute

    return self.cursor.execute(sql, params)

  File "C:\Python36\lib\site-packages\django\db\backends\sqlite3\base.py", line 328, in execute

    return Database.Cursor.execute(self, query, params)

django.db.utils.IntegrityError: NOT NULL constraint failed: core_profile.user_id