public function destroy()
{
// poista kommentit
Comment::delete_all_from_recipe($this->id);
//poista ainesosat
Ingredient::delete_from_recipe($this->id);
Ingredient::delete_unused();
//poista avainsanat
Keyword::delete_junctions($this->id);
Keyword::delete_unused();
$query = DB::connection()->prepare("DELETE FROM Recipe WHERE id = :id");
$query->execute(array('id' => $this->id));
}