fix: Date format in sales/purchases APIs.

fix: Algorithm FIFO cost calculate method.

server/src/database/migrations/20200715193633_create_sale_invoices_table.js

@@ -15,6 +15,7 @@ exports.up = function(knex) {
     table.decimal('balance', 13, 3);
     table.decimal('payment_amount', 13, 3);
 
+    table.string('inv_lot_number');
     table.timestamps();
   });  
 };