Initial release of Discourse

db/migrate/20121123054127_make_post_number_distinct.rb

@@ -0,0 +1,31 @@
+class MakePostNumberDistinct < ActiveRecord::Migration
+  def up
+
+    Topic.exec_sql('update posts p
+set post_number = calc 
+from
+(
+	select 
+		id, 
+		post_number, 
+		topic_id, 
+		row_number() over (partition by topic_id order by post_number, created_at) calc
+	from posts 
+	where topic_id in (
+	select topic_id from posts
+	  group by topic_id, post_number
+	  having count(*)>1
+	)
+
+) as X 
+where calc <> p.post_number and X.id = p.id')
+
+    remove_index :posts, :forum_thread_id_and_post_number
+    add_index :posts, [:topic_id, :post_number], :unique => true
+  end
+
+  def down
+    # don't want to mess with the index ... its annoying 
+    raise ActiveRecord::IrreversibleMigration
+  end
+end