public function changeKategory(){
        $this->isAdmin();

        $db = new DB();

        //zmiana kolejnosci - tylko!
        if($this->post["CatNewNumber"]>$this->post["CatOldNumber"]){
            $db -> query("SELECT id,kolejnosc FROM forum_category WHERE kolejnosc > :CatOldNumber AND kolejnosc <= :CatNewNumber ORDER BY kolejnosc ASC");
            $db -> bind (':CatOldNumber', $this->post["CatOldNumber"]);
            $db -> bind (':CatNewNumber', $this->post["CatNewNumber"]);
            $wyniki = $db -> resultSet();

            foreach($wyniki as $kategoria){
                $kategoria['kolejnosc']--;

                $db -> query("UPDATE forum_category SET kolejnosc = :kolejnoscNowa WHERE id = :id");
                $db -> bind(':kolejnoscNowa', $kategoria['kolejnosc']);
                $db -> bind(':id', $kategoria['id']);
                $db->execute();
            }

            $db -> query("UPDATE forum_category SET name = :NewName, opis = :NewDesc, kolejnosc = :CatNewNumber WHERE id = :CatId");
            $db -> bind (':NewName', $this->post['CatNewName']);
            $db -> bind (':NewDesc', $this->post['CatNewDesc']);
            $db -> bind (':CatNewNumber', $this->post['CatNewNumber']);
            $db -> bind (':CatId', $this->post['CatId']);
            $db -> execute();

        }elseif($this->post["CatNewNumber"]<$this->post["CatOldNumber"]){
            $db -> query("SELECT id,kolejnosc FROM forum_category WHERE kolejnosc < :CatOldNumber AND kolejnosc >= :CatNewNumber ORDER BY kolejnosc DESC");
            $db -> bind (':CatOldNumber', $this->post["CatOldNumber"]);
            $db -> bind (':CatNewNumber', $this->post["CatNewNumber"]);
            $wyniki = $db -> resultSet();

            foreach($wyniki as $kategoria){
                $kategoria['kolejnosc']++;

                $db -> query("UPDATE forum_category SET kolejnosc = :kolejnoscNowa WHERE id = :id");
                $db -> bind(':kolejnoscNowa', $kategoria['kolejnosc']);
                $db -> bind(':id', $kategoria['id']);
                $db->execute();
            }

            $db -> query("UPDATE forum_category SET name = :NewName, opis = :NewDesc, kolejnosc = :CatNewNumber WHERE id = :CatId");
            $db -> bind (':NewName', $this->post['CatNewName']);
            $db -> bind (':NewDesc', $this->post['CatNewDesc']);
            $db -> bind (':CatNewNumber', $this->post['CatNewNumber']);
            $db -> bind (':CatId', $this->post['CatId']);
            $db -> execute();
        }else{
            $db -> query("UPDATE forum_category SET name = :NewName, opis = :NewDesc WHERE id = :CatId");
            $db -> bind (':NewName', $this->post['CatNewName']);
            $db -> bind (':NewDesc', $this->post['CatNewDesc']);
            $db -> bind (':CatId', $this->post['CatId']);
            $db -> execute();
        }
        Messages::setSuccess("Kategoria zmieniona");
        header("Location:http://".ROOT_APP_URL."/forum");
    }