public function addAcademicYear()
 {
     $this->load->model('Academic_year_model');
     $p = new Academic_year_model();
     $p->academic_year = $this->input->post('academic_year');
     $result = $p->addAcademicYear();
     if (!$result) {
         echo mysqli_error($result);
     } else {
         redirect('academic_year/loadAllAcademicYears', 'refresh');
     }
 }