Oops, don't return body_id=0 items for "-fits:blue-acara"

Right, fitting isn't just body_id = this one, it's also body_id=0!

Anyway, doing this query on its own is still deathly slow, I wonder if
the idea I had about left joins (back when I was still working in a
Rails version that didn't support it lol) could help! Might poke at
that a smidge.

app/models/item.rb

@@ -103,7 +103,11 @@ class Item < ApplicationRecord
     # bother looking into this, but one thing I notice is items with no assets
     # somehow would not match either scope in this impl (but LEFT JOIN would!)
     joins(:swf_assets).group(i[:id]).
-      having('FIND_IN_SET(?, GROUP_CONCAT(body_id)) = 0', body_id).
+      having(
+        "FIND_IN_SET(?, GROUP_CONCAT(body_id)) = 0 AND " +
+        "FIND_IN_SET(0, GROUP_CONCAT(body_id)) = 0",
+        body_id
+      ).
       distinct
   }