public async Task <IHttpActionResult> Put(CourseDTO courseDTO, int id)
        {
            if (!ModelState.IsValid)
            {
                return(BadRequest(ModelState));
            }

            if (courseDTO.CourseId != id)
            {
                return(BadRequest());
            }

            Course course = await courseService.GetById(id);

            if (course == null)
            {
                return(NotFound());
            }

            try
            {
                Course _course = mapper.Map <Course>(courseDTO);
                _course = await courseService.Update(_course);

                return(Ok(_course));
            }
            catch (Exception ex)
            {
                return(InternalServerError(ex));
            }

            return(Ok());
        }