\connect postgres

drop database if exists pg_graph;
create database pg_graph;

\connect pg_graph

create table roles (
  id integer generated by default as identity primary key,
  name text not null
);

create table role_groups (
  id integer generated by default as identity primary key,
  child_role_id integer not null references roles(id),
  parent_role_id integer not null references roles(id)
);