removing broken code from old migrations

migrations.moon

@@ -27,26 +27,9 @@ import Tracks, Tags from require "models"
     }
       add_column "tracks", unpack column
   [3]: =>
-    -- NOTE: bad migration! (introduces more tags than it should)
-    for track in *Tracks\select "*"
-      tags = ""
-      for field in *{"artist", "mood", "link", "genre"}
-        if track[field]
-          tags ..= " #{field}:#{track[field]}"
-      if #tags > 0
-        track.tags = process_tags trim(track.tags or "untagged") .. tags
-        track\update "tags"
+    return true -- formerly a bad migration
   [4]: =>
-    -- NOTE: bad migration! (doesn't save changes to database)
-    for track in *Tracks\select "*"
-      tags = ""
-      for field in *{"artist", "mood", "link", "genre"}
-        if track[field] and #track[field] > 0
-          tags ..= " #{field}:#{track[field]}"
-      if #tags > 0
-        track.tags = process_tags "untagged" .. tags
-      else
-        track.tags = " untagged "
+    return true -- formerly a bad migration
   [5]: =>
     create_table "tags", {
       { "id", types.serial primary_key: true }