diff --git a/serviceWorker.js b/serviceWorker.js
index e4d31da..fdd8914 100644
--- a/serviceWorker.js
+++ b/serviceWorker.js
@@ -1,6 +1,6 @@
 
 var APP_SHELL_VERSION = 2;
-var APP_SHELL_CACHE = "inventur_shell-${APP_SHELL_VERSION}";
+var APP_SHELL_CACHE = `inventur_shell-${APP_SHELL_VERSION}`;
 var urlsToCache = [
     'css/lib/materialize.min.css',
     'js/lib/materialize.min.js',