Update vehicles_controller.rb

app/controllers/vehicles_controller.rb

@@ -103,7 +103,7 @@ class VehiclesController < ApplicationController
   
   # returns a dynamic list of vehicles owned by a customer
   def update_vehicles
-    @vehicles = Customer.find_by_id(params[:customer_id].to_i).vehicles
+    @vehicles = Customer.find_by(customer_id: params[:customer_id].to_i).vehicles
     respond_to do |format|
       format.html { render(:text => "not implemented") }
       format.js