sudo apt-get install postgresql
Step 6: Create a Database User Role for Handling Odoo Databases
Next, a password for the distinctive user should be defined, which is needed later in the conf file:
sudo su - postgres
createuser --createdb --username postgres --no-createrole --no-superuser --pwprompt odoo15
Make the defined user a superuser
psql
ALTER USER odoo15 WITH SUPERUSER;
And Exit from psql and also from Postgres user
\q
exit