how to create a new user on postgresql code example
Example 1: create db user postgres
sudo -u postgres psql
postgres=# create database mydb;
postgres=# create user myuser with encrypted password 'mypass';
postgres=# grant all privileges on database mydb to myuser;
Example 2: how to create new user and database postgresql in ubuntu
psql=# grant all privileges on database <dbname> to <username> ;