DO
      $do$
      BEGIN
         IF NOT EXISTS (
            SELECT 
            FROM   pg_catalog.pg_roles
            WHERE  rolname = 'user1') THEN
      
            CREATE ROLE user1 LOGIN PASSWORD 'password';
         END IF;
      END
      $do$;
      
      GRANT ALL PRIVILEGES ON DATABASE tbase TO user1;
      GRANT ALL PRIVILEGES ON ALL TABLES in schema public to user1;
      GRANT ALL PRIVILEGES ON ALL SEQUENCES IN SCHEMA public to user1;
      GRANT ALL PRIVILEGES ON ALL FUNCTIONS IN SCHEMA public to user1;

ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT ON TABLES TO user1;