{:up ["CREATE TABLE customer_products (
  id SERIAL,
  customer_id INT,
  product_id INT,
  amount NUMERIC,
  price BIGINT,
  PRIMARY KEY(id),
  CONSTRAINT fk_customer FOREIGN KEY(customer_id) REFERENCES customers(id),
  CONSTRAINT fk_product FOREIGN KEY(product_id) REFERENCES products(id)
)"
      "ALTER TABLE products ADD price BIGINT"
      "ALTER TABLE order_products ADD price BIGINT"]
 :down ["ALTER TABLE products DROP COLUMN price"
        "ALTER TABLE order_products DROP COLUMN price"
        "DROP TABLE customer_products"]}