public ActionResult TeacherLogin(LoginViewModel model, string returnUrl)
        {
            var objUtilities         = new Utilities.Utilities();
            var validateTeacherLogin = objUtilities.ValidateTeacherLogin(model);

            if (validateTeacherLogin)
            {
                var courseIdTaughtByTeacher = objUtilities.FetchCourseIdTaughtByTeacher(model.Username);
                return(RedirectToAction("TeacherHome", "Home", new { courseId = courseIdTaughtByTeacher }));
            }
            ModelState.AddModelError("", "Invalid login attempt.");
            return(View(model));
        }