Store carts sessions in database (#365)

migrations/000.462.sql

@@ -0,0 +1,20 @@
+-- Store carts in database
+
+DROP TABLE IF EXISTS cart_cookies, cart_users, cart_sessions;
+
+CREATE TABLE cart_sessions (
+    id               INTEGER GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+    market_locale_id INTEGER NOT NULL REFERENCES market_locales (id),
+    public_id        TEXT NOT NULL,
+    active           BOOLEAN NOT NULL DEFAULT TRUE,
+    content          TEXT,
+    revision         INTEGER NOT NULL DEFAULT 0,
+    inactive_reason  TEXT,
+    created          timestamp with time zone NOT NULL DEFAULT now(),
+    last_modified    timestamp with time zone NOT NULL DEFAULT now()
+);
+CREATE UNIQUE INDEX ON cart_sessions (public_id);
+
+-- last_modified reflects the last user interaction/modification of the cart.
+-- It it not auto updated via trigger, to avoid having it update on non-user interactions, like us expiring the cart.
+COMMENT ON COLUMN cart_sessions.last_modified IS 'Last update of cart contents';