update backend

frontend/src/api.js

@@ -1,6 +1,6 @@
 import axios from 'axios';
 
-const API_URL = 'http://localhost:5000/api'; // Update this with your backend URL
+const API_URL = 'http://backend:5000/api'; // Update this with your backend URL
 
 export const getInvoices = async () => {
   const response = await axios.get(`${API_URL}/invoices`);