Add expected_amount to Invoice

expected_amount returns the sum of all associated orders together with
the transport costs.

app/views/finance/invoices/show.html.haml

@@ -29,10 +29,14 @@
         %dd><
           - @invoice.orders.order(:ends).each_with_index do |order, index|
             - sum = order.sum
-            - total += sum
+            - transport = order.transport || 0
+            - total += sum + transport
             = ', ' if index > 0
             = link_to format_date(order.ends), new_finance_order_path(order_id: order)
-            = ' (' + number_to_currency(sum) + ')'
+            = ' (' + number_to_currency(sum)
+            - if transport != 0
+              = ' + ' + number_to_currency(transport)
+            = ')'
 
       %dt= heading_helper(Invoice, :number) + ':'
       %dd= @invoice.number

app/views/finance/invoices/unpaid.html.haml

@@ -8,12 +8,17 @@
     - invoices_text = []
     %p
     - for invoice in invoices
+      - invoice_amount_diff = invoice.expected_amount - invoice.net_amount
       - invoices_sum += invoice.amount
       - invoices_text << invoice.number
       = link_to finance_invoice_path(invoice) do
         = format_date invoice.date
         = ' ' + invoice.number
       = ' ' + number_to_currency(invoice.amount)
+      - if invoice_amount_diff != 0
+        %span{style: "color:#{invoice_amount_diff < 0 ? 'red' : 'green'}"}
+          = invoice_amount_diff > 0 ? '+' : '-'
+          = number_to_currency(invoice_amount_diff.abs)
       - if invoice.attachment_data?
         = link_to finance_invoice_attachment_path(invoice) do
           = glyph :download