[postgresql] PostgreSQL: How to change PostgreSQL user password?

This was the first result on google, when I was looking how to rename a user, so:

ALTER USER <username> WITH PASSWORD '<new_password>';  -- change password
ALTER USER <old_username> RENAME TO <new_username>;    -- rename user

A couple of other commands helpful for user management:

CREATE USER <username> PASSWORD '<password>' IN GROUP <group>;
DROP USER <username>;

Move user to another group

ALTER GROUP <old_group> DROP USER <username>;
ALTER GROUP <new_group> ADD USER <username>;