Here's my Postgres database tables: 
```
CREATE TABLE "public"."documents" (
 "id" int8 NOT NULL DEFAULT nextval('documents\_id\_seq'::regclass),
 "url" varchar,
 "file\_name" varchar,
 "order\_id" int8,
 "inserted\_at" timestamp NOT NULL,
 "updated\_at" timestamp NOT NULL,
 CONSTRAINT "documents\_order\_id\_fkey" FOREIGN KEY ("order\_id") REFERENCES "public"."orders"("id"),
 PRIMARY KEY ("id")
);
```

Write a SQL query that returns the file name, and url for documents that belong to the order with the id of 6, sorted by time updated:
user