Add user.id to tracking properties

plugins/c9.vfs.server/vfs.server.js

@@ -320,7 +320,7 @@ function plugin(options, imports, register) {
             Date.now() > user.lastVfsAccess + VFS_ACTIVITY_WINDOW) {
             
             analytics.identifyClean(user);
-            analytics.trackClean(user, "VFS is active");
+            analytics.trackClean(user, "VFS is active", { uid: user.id });
             
             user.lastVfsAccess = Date.now();
             user.save(function() {});