How to Hide the "Woot Watcher" Admin Menu

function plt_hide_wordpress_woot_watcher_menus() {
	//Hide the "Settings → Woot Watcher" menu.
	remove_submenu_page('options-general.php', 'wordpress-woot-watcher/wpwootwatcher.php');
}

add_action('admin_menu', 'plt_hide_wordpress_woot_watcher_menus', 11);

Where do I put this code?