psql -U postgres

CREATE DATABASE acme;

\l

SELECT * FROM pg_user;

CREATE USER devuser WITH PASSWORD '123456';

SELECT * FROM pg_user;

ALTER USER devuser WITH PASSWORD:

SELECT * FROM pg_user;

UPDATE pg_shadow SET passwd = 'something' WHERE username = 'devuser';

GRANT ALL ON database acme TO devuser;

\q

psql -U devuser

\c