/// <summary>
        /// Create user
        /// </summary>
        /// <param name="userName"></param>
        /// <param name="firstName"></param>
        /// <param name="lastName"></param>
        /// <param name="email"></param>
        /// <param name="password"></param>
        /// <returns>bolean result</returns>
        public bool Create(string userName, string firstName, string lastName, string email, string password)
        {
            bool createResult = false;
            UserEntity user = new UserEntity();

            if (_users.SingleOrDefault(u => u.UserName == userName) == null)
            {
                string passwordSalt = CreateSalt();

                user.Id = GenerateNewID();
                user.UserName = userName;
                user.FirstName = firstName;
                user.LastName = lastName;
                user.Email = email;
                user.PasswordSalt = passwordSalt;
                user.Password = CreatePasswordHash(password, passwordSalt);
                user.CreatedUTC = DateTime.Now;
                user.LastLoginDate = DateTime.Now;
                user.UserSettingId = 1;
                user.UserPhoto = @"/Images/UserPhoto/medveput.jpg";
                user.IsActivated = false;
                user.IsLockedOut = false;
                user.LastLockedOutDate = user.CreatedUTC;

                _users.Add(user);
                createResult = true;
            }
            return createResult;
        }
        /// <summary>
        /// Update current user
        /// </summary>
        /// <param name="user"></param>
        /// <returns>bolean result</returns>
        public bool Update(UserEntity user)
        {
            bool updateResult = false;

            UserEntity old = _users.SingleOrDefault(u => u.Id == user.Id);
            if (old != null)
            {
                old.Email = user.Email;
                old.FirstName = user.FirstName;
                old.LastName = user.LastName;
                updateResult = true;
            }

            return updateResult;
        }