Replace PrototypeR4 by Orbit.

Move session into mongoid_store.
Reset session when sing_in.

app/controllers/admin/sessions_controller.rb

@@ -0,0 +1,8 @@
+class SessionsController < Devise::SessionsController
+
+  def create 
+    super
+    reset_session
+  end
+
+end

app/models/session.rb

@@ -0,0 +1,12 @@
+class Session
+  include Mongoid::Document
+  include Mongoid::Timestamps
+  
+  def self.sweep(time = 1.hour)
+    if time.is_a?(String)
+      time = time.split.inject { |count, unit| count.to_i.send(unit) }
+    end
+ 
+    delete_all "updated_at < '#{time.ago.to_s(:db)}' OR created_at < '#{2.days.ago.to_s(:db)}'"
+  end
+end