now using ActiveModel::Dirty. only writes to database if model.changed?

lib/couchrest/model/casted_array.rb

@@ -5,6 +5,7 @@
 
 module CouchRest::Model
   class CastedArray < Array
+    include CouchRest::Model::Dirty
     attr_accessor :casted_by
     attr_accessor :property
 
@@ -14,15 +15,34 @@ module CouchRest::Model
     end
     
     def << obj
+      couchrest_parent_will_change!
       super(instantiate_and_cast(obj))
     end
     
     def push(obj)
+      couchrest_parent_will_change!
       super(instantiate_and_cast(obj))
     end
+
+    def pop
+      couchrest_parent_will_change!
+      super
+    end
+
+    def shift
+      couchrest_parent_will_change!
+      super
+    end
+
+    def unshift(obj)
+      couchrest_parent_will_change!
+      super(obj)
+    end
     
     def []= index, obj
-      super(index, instantiate_and_cast(obj))
+      value = instantiate_and_cast(obj)
+      couchrest_parent_will_change! if value != self[index]
+      super(index, value)
     end
 
     protected