Use Active Record session store

db/migrate/20110804225816_add_sessions_table.rb

@@ -0,0 +1,16 @@
+class AddSessionsTable < ActiveRecord::Migration
+  def self.up
+    create_table :sessions do |t|
+      t.string :session_id, :null => false
+      t.text :data
+      t.timestamps
+    end
+
+    add_index :sessions, :session_id
+    add_index :sessions, :updated_at
+  end
+
+  def self.down
+    drop_table :sessions
+  end
+end