fix docker-compose networking

docker-compose.yml

@@ -9,6 +9,8 @@ services:
       - "1307:80"
     depends_on:
       - backend
+    networks:
+      - app-network
 
   backend:
     build:
@@ -16,3 +18,9 @@ services:
       dockerfile: Dockerfile
     ports:
       - "1308:8080"
+    networks:
+      - app-network
+
+networks:
+  app-network:
+    driver: bridge

frontend/src/RelayForm.tsx

@@ -8,7 +8,7 @@ type Assignment = {
   events: string[];
 };
 
-const backend = axios.create({ baseURL: "http://localhost:1307" });
+const backend = axios.create({ baseURL: "http://backend:1307" });
 
 const RelayForm: React.FC = () => {
   const [forms, setForms] = useState<{ [key: string]: React.ReactNode }>({});