Add project readme

After seeing some changes get pushed up and not being able to see if they were on the pre-release hosted site, I decided to try my hand at running it locally. It wasn't bad, but I've gone ahead and added a README to add the instruction that I wish I had. That said, because I didn't know what I was doing, there's a very strong chance there's a better approach to the Building Locally steps than what I've provided. I can confirm they work for me, however.