Hotfix: fix add new rate in rating table

db/migrations/stored/R__functions.sql

@@ -43,7 +43,7 @@ BEGIN
           view_disciplines_recordbooks.DisciplineID = pDisciplineID
     LIMIT 1;
 
-    RETURN (vAttachType <=> 'attach');
+    RETURN 'attach' = COALESCE(vAttachType, 'attach');
 END //
 
 # check, that teacher teach this course