text: DROP TABLE IF EXISTS APPOINTMENT;
  DROP TABLE IF EXISTS JWT;
  DROP TABLE IF EXISTS SELLER;
  DROP TABLE IF EXISTS USERS;
  
  CREATE EXTENSION IF NOT EXISTS "uuid-ossp";
  
  CREATE TABLE USERS(
    id uuid DEFAULT uuid_generate_v4 () PRIMARY KEY,
    user_name VARCHAR(100) UNIQUE,
    hashed_password VARCHAR(250) NOT NULL,
    email VARCHAR(150) NOT NULL UNIQUE,
    is_seller BOOLEAN DEFAULT FALSE,
    created_at timestamp not null default current_timestamp
  );
  
  CREATE TABLE JWT(
    id uuid DEFAULT uuid_generate_v4 () PRIMARY KEY,
    user_id uuid NOT NULL UNIQUE,
    access_token VARCHAR(250) NOT NULL,
    refresh_token VARCHAR(250) NOT NULL,
    created_at timestamp not null default current_timestamp,
    FOREIGN KEY (user_id) REFERENCES USERS(id)
  );
  
  CREATE TABLE SELLER(
    id uuid DEFAULT uuid_generate_v4 () PRIMARY KEY,
    user_id uuid NOT NULL UNIQUE,
    seller_name VARCHAR(100) UNIQUE,
    created_at timestamp not null default current_timestamp,
    FOREIGN KEY (user_id) REFERENCES USERS(id)
  );
  
  CREATE TABLE APPOINTMENT(
    id uuid DEFAULT uuid_generate_v4 () PRIMARY KEY,
    seller_id uuid NOT NULL,
    buyer_name VARCHAR(250),
    appointment_description TEXT,
    appointment_status VARCHAR(250) NOT NULL DEFAULT 'PENDING',
    created_at timestamp not null default current_timestamp
  );