Add this to the top of plugin file

require 'plugin-update-checker/plugin-update-checker.php';
$myUpdateChecker = Puc_v4_Factory::buildUpdateChecker(
	'http://repository.caged.fish/updates/?action=get_metadata&slug=CHANGE_TO_FOLDER_NAME',
	__FILE__,
	'CHANGE_TO_FOLDER_NAME'
);