Make coupon subcodes findable

The previous code was able to find coupons by code, but there was no way to find them by their subcodes.

Author: oboxodo

lib/chargify_api_ares/resources/coupon.rb

@@ -7,7 +7,7 @@ def self.find_all_by_product_family_id(product_family_id)
     end
 
     def self.find_by_product_family_id_and_code(product_family_id, code)
-      find(:one, :from => :lookup, :params => {:product_family_id => product_family_id, :code => code})
+      find(:one, :from => :find, :params => {:product_family_id => product_family_id, :code => code})
     end
 
     def self.validate(params = {})

spec/resources/coupon_spec.rb

@@ -5,7 +5,7 @@
     let(:existing_coupon) { build(:coupon, :code => '20OFF') }
 
     before(:each) do
-      FakeWeb.register_uri(:get, "#{test_domain}/coupons/lookup.xml?code=#{existing_coupon.code}&product_family_id=10", :body => existing_coupon.attributes.to_xml)
+      FakeWeb.register_uri(:get, "#{test_domain}/coupons/find.xml?code=#{existing_coupon.code}&product_family_id=10", :body => existing_coupon.attributes.to_xml)
     end
 
     it "finds the correct coupon by product family and code" do