text: create table posts (
    id serial primary key,
    content text,
    author varchar(255)
  );
  create table comments (
    id serial primary key,
    content text,
    author varchar(255),
    post_id integer references posts(id)
  );
  create table users (
    id serial primary key,
    username text,
    password varchar(255)
  --   post_id integer references posts(id)
  );