How to create read only user in PostgreSQL

read-access.sql

-- Create a group
CREATE ROLE readaccess;

-- Grant access to existing tables #sidenote: please switch to DB for which you want to give access
GRANT USAGE ON SCHEMA public TO readaccess;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO readaccess;

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

-- Create a final user with password
CREATE USER tomek WITH PASSWORD 'secret';
GRANT readaccess TO tomek;