FEATURE: add a way to map arbitrary urls to a topic, post, or category. Useful for sites that have migrated to Discourse and want to redirect from their old site to Discourse with 301 redirects.

db/migrate/20140828172407_create_permalinks.rb

@@ -0,0 +1,14 @@
+class CreatePermalinks < ActiveRecord::Migration
+  def change
+    create_table :permalinks do |t|
+      t.string :url, null: false
+      t.integer :topic_id
+      t.integer :post_id
+      t.integer :category_id
+
+      t.timestamps
+    end
+
+    add_index :permalinks, :url
+  end
+end