How to Hide IgnitionDeck Admin Menus

function plt_hide_ignitiondeck_menus() {
	//Hide the "Plugins → Install Plugins" menu.
	remove_submenu_page('plugins.php', 'idf-plugins');
	//Hide the "IgnitionDeck" menu.
	remove_menu_page('idf');
}

add_action('admin_menu', 'plt_hide_ignitiondeck_menus', 101);

Where do I put this code?