https://medium.com/coding-blocks/creating-user-database-and-adding-access-on-postgresql-8bfcd2f4a91e
https://www.cyberciti.biz/faq/howto-add-postgresql-user-account/
$ sudo -u postgres psql
Create User
$ sudo -u postgres createuser <username>
Creating Database
$ sudo -u postgres createdb <dbname>
Giving the user a password
$ sudo -u postgres psql
psql=# alter user <username> with encrypted password '<password>';
Granting privileges on database
psql=# grant all privileges on database <dbname> to <username> ;