Add callback to job queue

[knownasilya]

https://github.com/Strider-CD/strider-simple-runner/blob/master/lib/index.js#L183

Also https://github.com/Strider-CD/strider-simple-runner/blob/master/lib/index.js#L329 needs the same code as https://github.com/Strider-CD/strider-simple-runner/blob/master/lib/index.js#L338-L350