Create read only user named "read_only_user" for database named "railway"

            
              
            
            CREATE USER read_only_user
WITH
  PASSWORD 'password';

GRANT CONNECT ON DATABASE railway TO read_only_user;

GRANT USAGE ON SCHEMA public TO read_only_user;

GRANT
SELECT
  ON ALL TABLES IN SCHEMA public TO read_only_user;

ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT
SELECT
  ON TABLES TO read_only_user;