How to create read only group & use on pg

-- 
-- To create the group 
-- 

-- Create a ro_group (readonly group)
CREATE ROLE ro_group;

-- Grant access to existing tables
GRANT USAGE ON SCHEMA public TO ro_group;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO ro_group;

-- Grant access to future tables
ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT ON TABLES TO ro_group;

-- Create a ro_user (readonly user) with password ('secret')
CREATE USER ro_user WITH PASSWORD 'secret';
GRANT ro_group TO ro_user;


-- 
-- To remove the group 
-- 

-- REVOKE ro_group
REVOKE USAGE ON SCHEMA public FROM ro_group;

-- REVOKE ro_group
REVOKE ALL ON public FROM ro_group;