return payment object type for creating a charge

lib/invoiced/charge.rb

@@ -1,7 +1,12 @@
 module Invoiced
     class Charge < Object
-        include Invoiced::Operations::Create
-
         OBJECT_NAME = 'charge'
+
+        def create(body={}, opts={})
+            response = @client.request(:post, endpoint(), body, opts)
+
+            payment = Payment.new(@client)
+            Util.convert_to_object(payment, response[:body])
+        end
     end
 end

test/invoiced/charge_test.rb

@@ -18,7 +18,7 @@ class ChargeTest < Test::Unit::TestCase
       charge = Charge.new(@client, 1234)
       charge = charge.create(:amount => 100, :payment_source_type => "card")
 
-      assert_instance_of(Invoiced::Charge, charge)
+      assert_instance_of(Invoiced::Payment, charge)
       assert_equal(charge.id, "a1b2c3")
     end
   end