public function getAll()
 {
     $sql = "SELECT * FROM reuse_and_repair_db.Category";
     $prepared = $this->db->link->prepare($sql);
     $success = $prepared->execute();
     $fetchAll = $prepared->fetchAll();
     foreach ($fetchAll as $row) {
         $category = new Category($row['category_id'], $row['category_name']);
         $this->results[] = $category->jsonSerialize();
     }
     return $this->getJSON();
 }