FIX: Detect more unsupported browsers

FIX: Detect more unsupported browsers

diff --git a/app/assets/javascripts/browser-detect.js b/app/assets/javascripts/browser-detect.js
index bdbbc27..57fb1e7 100644
--- a/app/assets/javascripts/browser-detect.js
+++ b/app/assets/javascripts/browser-detect.js
@@ -1,3 +1,3 @@
-if (!window.WeakMap || !window.Promise) {
+if (!window.WeakMap || !window.WeakSet || !window.Promise) {
   window.unsupportedBrowser = true;
 }

GitHub sha: 1cd8c6ce