PostgreSQL compatibility for FixPhotoShareVisibilities migration.

db/migrate/20111023230730_fix_photo_share_visibilities.rb

@@ -2,9 +2,25 @@ class FixPhotoShareVisibilities < ActiveRecord::Migration
   class Photo < ActiveRecord::Base; end
 
   def self.up
-    raise 'migration currently only compatable with mysql' if postgres?
+    return  if ! Photo.first.respond_to?(:tmp_old_id)
 
-    if Photo.first.respond_to?(:tmp_old_id)
+    if postgres?
+      ['aspect_visibilities', 'share_visibilities'].each do |vis_table|
+        execute "UPDATE #{vis_table} SET shareable_type = 'Post'"
+
+        execute %{
+          UPDATE
+            #{vis_table}
+          SET
+              shareable_type = 'Photo'
+            , shareable_id   = photos.id
+          FROM
+            photos
+          WHERE
+            #{vis_table}.shareable_id = photos.tmp_old_id
+        }
+      end
+    else
       ['aspect_visibilities', 'share_visibilities'].each do |vis_table|
         ActiveRecord::Base.connection.execute <<SQL
         UPDATE #{vis_table}