text: -- Creating table to store app user details
  CREATE TABLE IF NOT EXISTS app_user (
    user_id INTEGER PRIMARY KEY,
    user_name VARCHAR(255) NOT NULL,
    email VARCHAR(255) NOT NULL UNIQUE,
    password VARCHAR(255) NOT NULL,
    role SMALLINT NOT NULL DEFAULT 0,
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
  );