Document that img_description_id is a comment id

It took me a bit of time to figure this out, and it seems non-obvious,
so I thought a comment would be appropriate.

Change-Id: Ibe7220ed8f9355e3025c257057754eb4d72384b9

diff --git a/maintenance/tables.sql b/maintenance/tables.sql
index 254ed38..df15abf 100644 (file)
--- a/maintenance/tables.sql
+++ b/maintenance/tables.sql
@@ -1173,7 +1173,7 @@ CREATE TABLE /*_*/image (
   -- see https://www.iana.org/assignments/media-types/
   img_minor_mime varbinary(100) NOT NULL default "unknown",
 
-  -- Description field as entered by the uploader.
+  -- Foreign key to comment table, which contains the description field as entered by the uploader.
   -- This is displayed in image upload history and logs.
   img_description_id bigint unsigned NOT NULL,