added rate plan charges to subscribe request to specify quantity

lib/zuora/objects/subscribe_request.rb

@@ -6,6 +6,7 @@ class SubscribeRequest < Base
     attr_accessor :payment_method
     attr_accessor :sold_to_contact
     attr_accessor :product_rate_plans
+    attr_accessor :rate_plan_charges
 
     attr_accessor :validation_errors
 
@@ -82,6 +83,15 @@ def create
                 rpd.__send__(zns, :RatePlan) do |rp|
                   rp.__send__(ons, :ProductRatePlanId, product_rate_plan.id)
                 end
+
+                rate_plan_charges.each do |product_rate_plan_charge|
+                  rpd.__send__(zns, :RatePlanChargeData) do |rpcd|
+                    rpcd.__send__(zns, :RatePlanCharge) do |rpc|
+                      rpc.__send__(ons, :ProductRatePlanChargeId, product_rate_plan_charge.product_rate_plan_charge_id)
+                      rpc.__send__(ons, :Quantity, product_rate_plan_charge.quantity)
+                    end
+                  end
+                end unless rate_plan_charges.nil?                              
               end
             end
           end

spec/zuora/objects/subscribe_request_spec.rb

@@ -203,6 +203,23 @@
         with_value(true)
     end
 
+    it "supports specifiying the charges quantity" do
+      MockResponse.responds_with(:subscribe_request_success) do
+        rpc = Zuora::Objects::RatePlanCharge.new
+        rpc.quantity = 12
+        rpc.product_rate_plan_charge_id = '123'
+        charges = Array.new
+        charges << rpc
+        subject.rate_plan_charges = charges
+        subject.should be_valid
+        sub_resp = subject.create
+        sub_resp[:success].should == true
+      end
+      xml = Zuora::Api.instance.last_request
+      xml.should have_xml("//env:Body/#{zns}:subscribe/#{zns}:subscribes/#{zns}:SubscriptionData/#{zns}:RatePlanData/#{zns}:RatePlanChargeData/#{zns}:RatePlanCharge/#{ons}:Quantity").
+        with_value("12")
+    end
+
     it "applies valid response data to the proper nested objects and resets dirty" do
       MockResponse.responds_with(:subscribe_request_success) do
         subject.should be_valid