protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                if (_userManager != null)
                {
                    _userManager.Dispose();
                    _userManager = null;
                }

                if (_signInManager != null)
                {
                    _signInManager.Dispose();
                    _signInManager = null;
                }

                if (db != null)
                {
                    db.Dispose();
                    db = null;
                }
            }



            base.Dispose(disposing);
        }