Ensure ActiveModel 3.2.x compatibility

couchrest_model.gemspec

@@ -25,7 +25,7 @@ Gem::Specification.new do |s|
 
   s.add_dependency(%q<couchrest>, "~> 1.1.2")
   s.add_dependency(%q<mime-types>, "~> 1.15")
-  s.add_dependency(%q<activemodel>, "~> 3.1.0")
+  s.add_dependency(%q<activemodel>, "~> 3.2.0")
   s.add_dependency(%q<tzinfo>, "~> 0.3.22")
   s.add_development_dependency(%q<rspec>, "~> 2.6.0")
   s.add_development_dependency(%q<json>, ["~> 1.5.1"])

lib/couchrest/model/base.rb

@@ -2,7 +2,8 @@ module CouchRest
   module Model
     class Base < CouchRest::Document
 
-      extend ActiveModel::Naming
+      extend  ActiveModel::Naming
+      include ActiveModel::Conversion
 
       include CouchRest::Model::Configuration
       include CouchRest::Model::Connection

spec/unit/dirty_spec.rb

@@ -33,11 +33,22 @@ def code; self['_id'] || @code; end
 
   describe "changes" do
 
-    it "should return changes on an attribute" do
-      @card = Card.new(:first_name => "matt")
-      @card.first_name = "andrew"
-      @card.first_name_changed?.should be_true
-      @card.changes.should == { "first_name" => ["matt", "andrew"] }
+    context "when new record" do
+      it "should return changes on an attribute" do
+        @card = Card.new(:first_name => "matt")
+        @card.first_name = "andrew"
+        @card.first_name_changed?.should be_true
+        @card.changes.should == { "first_name" => [nil, "andrew"] }
+      end
+    end
+
+    context "when persisted" do
+      it "should return changes on an attribute" do
+        @card = Card.create!(:first_name => "matt")
+        @card.first_name = "andrew"
+        @card.first_name_changed?.should be_true
+        @card.changes.should == { "first_name" => ["matt", "andrew"] }
+      end
     end
 
   end