added paths to svelte.config

frontend/svelte.config.js

@@ -1,12 +1,17 @@
 import adapter from '@sveltejs/adapter-node';
 
+const isProduction = process.env.NODE_ENV === 'production';
+
 /** @type {import('@sveltejs/kit').Config} */
 const config = {
 	kit: {
 		// adapter-auto only supports some environments, see https://svelte.dev/docs/kit/adapter-auto for a list.
 		// If your environment is not supported, or you settled on a specific environment, switch out the adapter.
 		// See https://svelte.dev/docs/kit/adapters for more information about adapters.
-		adapter: adapter()
+		adapter: adapter(),
+		paths: {
+			base: isProduction ? '/backend' : ''
+		}
 	}
 };