CREATE TABLE GROUP_PRODUCTS (
	id SERIAL PRIMARY KEY,
	name CHARACTER VARYING(100), 
	user_id INTEGER NOT NULL,
	CONSTRAINT GROUP_PRODUCTS_USER_ID_FOREIGN FOREIGN KEY (USER_ID) REFERENCES USERS (ID) 
);

CREATE TABLE GROUP_PRODUCT_USERS ( 
	id SERIAL PRIMARY KEY,
	group_product_id INTEGER NOT NULL,
	user_id INTEGER NOT NULL,
	CONSTRAINT GROUP_PRODUCT_USERS_GROUP_PRODUCT_ID_FOREIGN FOREIGN KEY (GROUP_PRODUCT_ID) REFERENCES GROUP_PRODUCTS (ID),
	CONSTRAINT GROUP_PRODUCT_USERS_USER_ID_FOREIGN FOREIGN KEY (USER_ID) REFERENCES USERS (ID) 
);