send feedback when a user registers

www/register/main.js

@@ -68,6 +68,12 @@ define([
             proxy.edPublic = result.edPublic;
             proxy.edPrivate = result.edPrivate;
 
+            // feedback API won't work because proxy wasn't loaded
+            $.ajax({
+                type: 'HEAD',
+                url: '/common/feedback.html?REGISTRATION=' + (+new Date());
+            });
+
             Cryptpad.whenRealtimeSyncs(result.realtime, function () {
                 Cryptpad.login(result.userHash, result.userName, function () {
                     if (sessionStorage.redirectTo) {