public RoleStore(OrmLiteIdentityDbContext context)
        {
            if (context == null)
            {
                throw new ArgumentNullException("context is null");
            }

            _context = context;
        }
        public UserStore(OrmLiteIdentityDbContext context)
        {
            if (context == null)
            {
                throw new ArgumentNullException(nameof(context));
            }

            _context = context;
        }