add checksum for menu sync

app/controllers/api/restaurant/menu_controller.rb

@@ -4,8 +4,25 @@ class Api::Restaurant::MenuController < Api::ApiController
   # Pull the default menu details and also other available (active) menus
   # Input Params - order_id
   def index
-    @menus = Menu.all
-    # @current_menu = Menu.current_menu
+    param_checksum = params[:checksum]
+    # checksum = File.readlines("public/checksums/menu_json.txt").pop.chomp
+
+    all_menu = Menu.all
+
+    # to hash
+    menu_array = []
+    all_menu.each do |m|
+      menu_array.push(m.to_json(:include => {:menu_categories => { :include => { :menu_items => { :include => [:menu_item_sets, :menu_item_instances => {:include => :menu_instance_item_sets}]} } }}))
+    end            
+                 
+    #export Checksum file generate by md5
+    menu_checksum = Digest::MD5.hexdigest(menu_array.to_json)
+
+    if menu_checksum != param_checksum
+      response.headers['CHECKSUM'] = menu_checksum
+      @menus = all_menu    
+    end
+    # @current_menu = Menu.current_menu    
   end
 
   #Description