I was using asdf as a manager of package managers (I note this because this is the only deviation I made from the beginning instructions).  

Anyways, after getting to starting up the rails server, The logs said that

Showing /Users/williamhancharek/code/picky/lib/jumpstart/app/views/layouts/jumpstart/application.html.erb where line #10 raised:

The asset "application.css" is not present in the asset pipeline.

Running 

RAILS_ENV=production rails assets:precompile

fixed it, but I don't know why everything didn't just work when just running rails s which I find troubling (what did I do wrong ahah)

You need to run bin/dev so that the cssbundling and jsbundling commands can watch and build your assets.

If you only run the Rails server by itself, you won't get any asset compilation happening.

I ran into the same issues you must make sure 'bin/setup' runs correct. 
Then run 'bin/dev'.

* Note to self - always read the readme.md even if you used the code base before! 

also you add "use a Procfile and a Procfile.dev", that way you can start/stop everything all at once.  What a time saver!