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
+      button#tourstart-btn.buttonset.one(onclick='stopStory()')
+          span.i18n_balloon_startscreen_btn Start
       // SSO experiment
       if userLogin == true
-        button#tourstart-btn.buttonset.one(onclick='stopStory()')
-          span.i18n_balloon_startscreen_btn Start
+        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