/// <summary>
 /// PUT api/TaiKhoan<br/>
 /// Updates an account that exists in server
 /// </summary>
 /// <param name="dangNhap">A json string that is defined as a DangNhap object</param>
 /// <returns>Code: 200 or 400 or 404</returns>
 public IHttpActionResult Put(DangNhap dangNhap)
 {
     if (!ModelState.IsValid)
     {
         return(BadRequest("Invalid request"));
     }
     if (DangNhap.UpdateAccount(dangNhap))
     {
         return(Ok());
     }
     return(NotFound());
 }