Start a new app quickly with all the good stuff already set up. And save a lot of time.
Fork this app and name it as you please. rgrep the old app name or have a look at this commit to know the spots where you need to replace the old name by your chosen app name.
Install Postgres 10.2 locally. Then create a user and two databases as follows.
$ psql postgres
> CREATE ROLE rails5applicationkickoffboost PASSWORD 'rails5applicationkickoffboost' NOSUPERUSER CREATEDB NOCREATEROLE INHERIT LOGIN;
> CREATE DATABASE rails5applicationkickoffboost OWNER rails5applicationkickoffboost;
> CREATE DATABASE rails5applicationkickoffboost_test OWNER rails5applicationkickoffboost;