public IHttpActionResult AddStudent(int id, Student newStudent)
        {
            // Checking if the object is not valid
            if (newStudent == null) throw new HttpResponseException(HttpStatusCode.PreconditionFailed);
            if (!ModelState.IsValid) throw new HttpResponseException(HttpStatusCode.PreconditionFailed);

            // Finding the course
            var course = _courses.Find(x => id == x.ID);
            if (course == null)
            {
                throw new HttpResponseException(HttpStatusCode.NotFound);
            }

            // Course was found, creating the student and adding
            // it to the user list
            Student student = new Student
            {
                SSN = newStudent.SSN,
                Name = newStudent.Name
            };
            course.Students.Add(student);
            var location = Url.Link("GetStudents", new { id = course.ID });
            return Created(location, student);
        }
        public IHttpActionResult AddStudentToCourse(int id, Student student)
        {
            //checking if the student being added is not of the right data type
            if (student == null)
            {
                throw new HttpResponseException(HttpStatusCode.PreconditionFailed);
            }

            foreach (Course c in _courses)
            {
                if (c.ID == id) {
                    _courses[_courses.IndexOf(c)].Students.Add(student);
                    var location = Url.Link("GetCourse", new { id = c.ID });
                    return Created(location, student);
                }
            }

            //return 404
            return NotFound();
        }