Initial release of Discourse

db/migrate/20130203204338_add_last_version_at_to_posts.rb

@@ -0,0 +1,9 @@
+class AddLastVersionAtToPosts < ActiveRecord::Migration
+  def change
+    add_column :posts, :last_version_at, :timestamp
+    execute "UPDATE posts SET last_version_at = COALESCE((SELECT max(created_at)
+                                                 FROM versions WHERE versions.versioned_id = posts.id
+                                                    AND versions.versioned_type = 'Post'), posts.created_at)"
+    change_column :posts, :last_version_at, :timestamp, null: false
+  end
+end