/// <summary>
        /// Signs in.
        /// </summary>
        /// <param name="userName">Name of the user.</param>
        /// <param name="createPersistentCookie">if set to <c>true</c> [create persistent cookie].</param>
        public void SignIn(string userName, bool createPersistentCookie)
        {
            ValidationUtility.ValidateRequiredStringValue(userName, "userName");

            FormsAuthentication.SetAuthCookie(userName, createPersistentCookie);
        }