add login/logout button to test user status

vcm/index.pug

@@ -176,13 +176,13 @@ header.tour-header.vcm-header-height.vcm-header-base.vcm-border-splash
         strong M4_Lab
         br
         | Platform
-      // SSO experiment
-      if userLogin == true
       button#tourstart-btn.buttonset.one(onclick='stopStory()')
           span.i18n_balloon_startscreen_btn Start
+      // SSO experiment
+      if userLogin == true
+        a(href="/logout") Logout
       else
-        button
-          span.i18n_balloon_startscreen_btn Login
+        a(href="/login") Login
     .dialog-image-balloon
     .balloon-left-edge
   // End of: Content Start Screen