def book_params
    params.require(:book).permit(:grandham_id, :language_id, :title, :isbn, :pages, :year,
                                 :description, :edition, :ddc, :volume, :series, :price,
                                 :length, :title_orginal, :illustrator, :note, :preface,
                                 :created_at, :updated_at, :approved, :published)