bugfix: allow CastedArrays to be assigned

(And be a bit more general about it)

lib/couchrest/model/property.rb

@@ -33,7 +33,7 @@ module CouchRest::Model
           data.keys.sort.each do |k|
             value << data[k]
           end
-        elsif value.class != Array
+        elsif !value.is_a?(Array)
           raise "Expecting an array or keyed hash for property #{parent.class.name}##{self.name}"
         end
         arr = value.collect { |data| cast_value(parent, data) }

spec/couchrest/casted_model_spec.rb

@@ -358,6 +358,14 @@ describe CouchRest::Model::CastedModel do
       @cat.toys << @toy2
     end
 
+    it 'should let you copy over casted arrays' do
+      question = Question.new
+      @course.questions << question
+      new_course = Course.new
+      new_course.questions = @course.questions
+      new_course.questions.should include(question)
+    end
+
     it "should reference the top document for" do
       @course.base_doc.should === @course
       @professor.casted_by.should === @course