Consistently name <username>, YOUR_USERNAME, YourUsername in git repo tutorial

[chase-metzger]

Problem

I noticed while following along with the "Git Repositories" tutorial that goes with Step 5 of VI's first steps, that there are inconsistent ways of referring to the readers Github username as a placeholder. Despite being quite familiar with navigating Github and using git cli this led to a little confusion on my part because it's referring to the same username, I believe, all the time.

Steps to reproduce the problem

open http://open-learning-exchange.github.io/#!./pages/vi/vi-github-and-repositories.md

Screenshots

Two examples below -

Proposed solution

Rewrite vi-github-and-repositories.md to be most consistent about how to refer to the readers Github username (where applicable).

I'm not sure of what I would call the shared username across the sections yet.

Suggestions?