Add time limit for inactive sessions

closes #8

app/javascript/controllers/notification_controller.js

@@ -4,6 +4,10 @@ export default class extends Controller {
   static targets = ["buttons", "countdown"]
 
   connect() {
+    // Devise timeoutable ends up adding a second flash message without content
+    // TODO investigate bug
+    if (this.element.textContent.trim() == "true") return;
+
     const timeoutSeconds = parseInt(this.data.get("timeout"));
 
     setTimeout(() => {