public IHttpActionResult Post(CourseRequestModel model)
        {
            if (!this.ModelState.IsValid)
            {
                return this.BadRequest(this.ModelState);
            }

            var course = new Course
            {
                Name = model.Name,
                Description = model.Description
            };

            this.data.Courses.Add(course);
            this.data.Courses.SaveChanges();

            return this.Ok(course);
        }
        public IHttpActionResult Put(int id, CourseRequestModel model)
        {
            if (!this.ModelState.IsValid)
            {
                return this.BadRequest(this.ModelState);
            }

            var course = this.data.Courses
                .All()
                .FirstOrDefault(c => c.Id == id);

            if (course == null)
            {
                return this.BadRequest("Course with id " + id + " does not exist!");
            }

            course.Name = model.Name;
            course.Description = model.Description;

            this.data.Courses.Update(course);
            this.data.Courses.SaveChanges();

            return this.Ok(model);
        }