update

Starting with Guard 2.0, Guard::Spork should inherit from Guard::Plugin
> [#] instead of Guard::Guard.
> [#] Please note that the constructor signature has changed from
> [#] Guard::Guard#initialize(watchers = [], options = {}) to
> [#] Guard::Plugin#initialize(options = {}).
> [#] For more information on how to upgrade for Guard 2.0, please head over
> [#] to: https://github.com/guard/guard/wiki/Upgrading-to-Guard-2.0#changes-in-guardguard