Customer review of a product.

Column	Type	Constraint	Description
shop	TEXT	PRIMARY KEY	Shop ID. (shop.id)
id	INTEGER		Identifier.
product_id	INTEGER	NOT NULL	Product ID. (product.id)
account_id	INTEGER	NOT NULL	Account ID who wrote the review. (account.mail)
rating	INTEGER	NOT NULL	Rating for the product. 5 levels. 1(Lowest) - 5(Highest).
title	TEXT	NOT NULL	Title.
comment	TEXT	NOT NULL	Comment content.
agreed	INTEGER	NOT NULL	Number of people who agrees with the review.
disagreed	INTEGER	NOT NULL	Number of people who disagrees with the review.
posted	DATE	NOT NULL	Posted date.

CREATE TABLE review(
shop        TEXT,
id          INTEGER,
product_id  INTEGER   NOT NULL,
account_id  INTEGER   NOT NULL,
rating      INTEGER   NOT NULL,
title       TEXT      NOT NULL,
comment     TEXT      NOT NULL,
agreed      INTEGER   NOT NULL,
disagreed   INTEGER   NOT NULL,
posted      DATE      NOT NULL,
PRIMARY KEY(shop, id));