public void AddCourseToStudent(int studentId, int courseId, int year, Semester semester)
        {
            StudentCourseAdapter studentCourse = new StudentCourseAdapter
            {
                StudentId        = studentId,
                CourseId         = courseId,
                RegisterYear     = year,
                RegisterSemester = semester
            };

            dal.AddStudentCourse(studentCourse);
        }