[#4183] Implemented FixedDeliverable#profit_left (was called profit_spent).

app/models/fixed_deliverable.rb

@@ -26,6 +26,12 @@ class FixedDeliverable < Deliverable
     budgets = labor_budget_total + overhead_budget_total
     (total || 0.0) - budgets
   end
+
+  # The amount of money remaining after expenses have been taken out
+  # Profit left = Total - Labor spent - Overhead spent
+  def profit_left
+    total_spent - labor_budget_spent - overhead_spent
+  end
   
   # Hardcoded value used as a wrapper for the old Budget plugin API.
   #