public async Task <HttpResponseMessage> CheckUserNameAndEmailExistence(string email, string userName)
        {
            if (!ModelState.IsValid)
            {
                return(Request.CreateResponse(HttpStatusCode.BadRequest));
            }

            registerManager = new RegisterManager();

            var isEmailExist = await registerManager.CheckEmailExistence(email);

            var isuserNameExist = await registerManager.CheckUserNameExistence(userName);

            bool[] existence = { isEmailExist, isuserNameExist };
            return(Request.CreateResponse(HttpStatusCode.OK, existence));
        }