It was meant in the style of "Setup and .. NginX/Redis/PostgreSQL", it assumed the reader knows about PostgREST (that's why the link is to a landing page and not to the homepage). subzero.cloud is BaaS (GraphQL & Rest api for your database).

Your comment is valid though, not everybody knows about PostgREST (but you should check it out :) http://postgrest.org/)