Jekyll: Writing a Theme, Part III: Gemming your theme
Here's some advice about how to let Bundler know where to find your gem while you are developing on your local machine so that you don't need to develop in public by pushing your gem up to GitHub all the time and without telling Bundler that your gem is, in fact, local in your Gemfile.
Once your local development is done, here's my reference for pushing it out to the world: How to Create and Publish a Jekyll Theme Gem - David Darnes.
I should really make a separation from the structRDFal demo site from the theme itself, even if that's just the background colours somewhere else...?