public void addAttendantToCourse(int courseId, int studentId) {
		if(!isValidId(courseId) || !isValidId(studentId)) {
			return;
		}
		
		Student student = studentDao.getStudent(studentId);
		Course course   = courseDao.getCourse(courseId);
		
		if(student != null && course != null) {
			course.getAttendants().add(student);
			//student.getCourses().add(course);
			courseDao.saveCourse(course);
			//studentDao.saveStudent(student);
		}
	}