Ummm, I'm pretty sure this is exactly what I need right now. Kudos. Currently our process is:

1) I mockup the design in Balsamiq

2) My designer creates the design in HTML/CSS and then pushes to git (using grunt/node/bower)

3) We screenshot and annotate using InvisionApp

4) repeat 3 and 4 until design looks good

If I understand correctly:

- This will load up my grunt server automatically based on the latest push to github

- I can then annotate that HTML/CSS front-end to my designer for feedback changes.

- No more screenshotting for me?!? This would be amazing.

Any chance you can integrate to Bitbucket? :)

EDIT: If so, please get in touch - happy to be your early evangelist and provide more feedback.