README: Describe reviewer workflow

[stevegt]

Add a section to the README, walking reviewers through how to set up a personal fork of the repo and review/accept PRs, probably something like:

Setup

1. fork repo
2. set github pages config so fork is viewable at https://username.github.io/nationofmakers.github.io/

Review/Publish PR

1. pull PR branch to local, push to fork
2. test, edit if needed
3. push any edits back to upstream PR branch
4. if no new edits were needed, merge PR to upstream master -- this will cause github to publish it on the public site
5. if new edits were needed, get someone else to review/merge (can be original submitter if they have merge auth)

[mkenigson]

Is this the "dug up, restored, and updated" language described in #52 ?

[stevegt]

No, this would be a new section in the README. Also see comment I'm adding right now in #52.