Only show last month's overflow

web/budgeting.html

@@ -28,6 +28,7 @@
         <th>Category</th>
         <th></th>
         <th></th>
+        <th>Leftover</th>
         <th>Assigned</th>
         <th>Activity</th>
         <th>Available</th>
@@ -40,6 +41,7 @@
         </td>
         <td>
         </td>
+        {{template "amount-cell" .AvailableLastMonth}}
         {{template "amount-cell" .Assigned}}
         {{template "amount-cell" .Activity}}
         {{template "amount-cell" .Available}}