Added initial content for Brunch chapters

[alxhill]

Added content from the blog post into the relevant chapters, as described in #5.

Sections to be written:

• Installation needs to be expanded
• Workflow
• Walkthrough
• Deployment
• When is Brunch the right choice?

[addyosmani]

Thanks @alxhill. This initial draft looks good. Looking forward to the other sections you're hoping to look at. Appreciate your time on this :)