add order number & invoice number to invoices

app/models/invoice/data_presenter.rb

@@ -86,6 +86,10 @@ class Invoice
       date
     end
 
+    def invoice_number
+      invoice.number
+    end
+
     def paid?
       data[:payment_state] == 'paid' || data[:payment_state] == 'credit_owed'
     end

app/views/spree/admin/orders/invoice3.html.haml

@@ -7,6 +7,16 @@
         %h6
           = "#{t('spree.admin.orders.invoice.issued_on')}: "
           = l @order.invoice_date
+    %tr{ valign: "top" }
+      %td{ :align => "left", colspan: 3 }
+        %h6
+          = "#{t('spree.admin.orders.invoice.order_number')}: "
+          = @order.number
+    %tr{ valign: "top" }
+      %td{ :align => "left", colspan: 3 }
+        %h6
+          = "#{t('spree.admin.orders.invoice.invoice_number')}: "
+          = @order.invoice_number
     %tr{ valign: "top" }
       %td{ :align => "left" }
         %h4

config/locales/en.yml

@@ -4106,6 +4106,8 @@ See the %{link} to find out more about %{sitename}'s features and to start using
           from: "From"
           to: "Bill to"
           shipping: "Shipping"
+          order_number: "Order Number"
+          invoice_number: "Invoice Number"
         note:
           note_label: "Note:"
           no_note_present: "No note provided."