text: CREATE EXTENSION IF NOT EXISTS "uuid-ossp";
  
  CREATE TABLE IF NOT EXISTS writers (
      writer_id UUID DEFAULT uuid_generate_v4(),
      name VARCHAR,
      PRIMARY KEY(writer_id)
  );
  
  CREATE TABLE IF NOT EXISTS posts(
      id SERIAL,
      title VARCHAR,
      subject VARCHAR,
      content VARCHAR,
      writer_id UUID,
      PRIMARY KEY(id),
      CONSTRAINT fk_writer_id FOREIGN KEY(writer_id) REFERENCES writers(writer_id)
  );