update shift

app/models/sale.rb

@@ -437,6 +437,15 @@ end
     return other
   end
 
+  def get_commerical_tax
+    tax = 0.0
+     self.sale_taxes.each do |tax|
+        if tax.tax_name == "Commerical Tax"
+           tax += tax.tax_payable_amount
+        end
+     end
+  end
+
   private
 
   def generate_custom_id