public function createCategory($account, $title)
 {
     $db = new Database();
     $data = array($account, $title);
     $data = $db->execute("SELECT * FROM categories WHERE account = ? AND title = ?", $data);
     $data->setFetchMode(PDO::FETCH_CLASS | PDO::FETCH_PROPS_LATE, 'CategoryEntity');
     $categoryEntity = $data->fetch();
     if ($categoryEntity) {
         return $categoryEntity;
     } else {
         $categoryEntity = new CategoryEntity();
         $categoryEntity->setAccount($account);
         $categoryEntity->setTitle($title);
         $categoryEntity->persist();
         return $categoryEntity;
     }
 }