fix: address code review findings

static/app.js

@@ -241,8 +241,8 @@ async function searchRoutes(formData) {
                 'Content-Type': 'application/json'
             },
             body: JSON.stringify({
-                from: formData.get('from'),
-                to: formData.get('to'),
+                from_city_id: formData.get('from'),
+                to_city_id: formData.get('to'),
                 date: formData.get('date')
             })
         });