text: CREATE TABLE users (
      id SERIAL PRIMARY KEY,
      name TEXT UNIQUE,
      password TEXT,
      created_at TIMESTAMP,
      is_admin BOOLEAN,
      is_visible BOOLEAN
  );
  CREATE TABLE areas (
      id SERIAL PRIMARY KEY,
      user_id INTEGER REFERENCES users,
      name TEXT,
      created_at TIMESTAMP,
      is_secret BOOLEAN,
      is_visible BOOLEAN
  );
  CREATE TABLE threads (
      id SERIAL PRIMARY KEY,
      user_id INTEGER REFERENCES users,
      area_id INTEGER REFERENCES areas,
      title TEXT,
      created_at TIMESTAMP,
      is_visible BOOLEAN
  );
  CREATE TABLE messages (
      id SERIAL PRIMARY KEY,
      user_id INTEGER REFERENCES users,
      thread_id INTEGER REFERENCES threads,
      content TEXT,
      created_at TIMESTAMP,
      is_visible BOOLEAN
  );
  CREATE TABLE users_areas (
      id SERIAL PRIMARY KEY,
      user_id INTEGER REFERENCES users,
      area_id INTEGER REFERENCES areas
  );