public IActionResult GetInstructorByEmail([FromQuery] string email)
 {
     try
     {
         var user          = _userManager.FindByNameAsync(email).Result;
         var instructor    = _instructorService.GetInstructorByUserId(user.Id);
         var instructorDTO = _mapper.Map <Instructor, InstructorDTO>(instructor);
         return(Ok(instructorDTO));
     }
     catch (Exception ex)
     {
         return(BadRequest(ex.Message));
     }
 }