In order to publish our application, we need to add our application and any changes we make over time to a "revision control system". It our case we're going to use git because it is (relatively) easy and it is what our app server, heroku, uses to deal with all changes.
In your terminal, try:
$ git init .
It doesn't look like anything really happened, but 'git init'
initialized its repository (repo) in a hidden directory called ".git".
You can see this by typing
ls -a (list all files).