Assign a doc to a workshop and not a course

files/db/update_v2_to_v3.sql

@@ -0,0 +1,6 @@
+ALTER TABLE docs ADD id_workshop int(10) unsigned DEFAULT NULL AFTER id_user;
+ALTER TABLE docs ADD INDEX(`id_workshop`);
+ALTER TABLE docs ADD FOREIGN KEY (`id_workshop`) REFERENCES workshops(`id_workshop`);
+UPDATE docs INNER JOIN courses USING(id_course) SET docs.id_workshop = courses.id_workshop;
+ALTER TABLE docs DROP FOREIGN KEY docs_ibfk_2;
+ALTER TABLE docs DROP id_course;