Add missing redir. for user docs intro.

Author: pwizla

docusaurus/vercel.json

@@ -35,6 +35,11 @@
       "destination": "/",
       "permanent": true
     },
+    {
+      "source": "/user-docs/intro",
+      "destination": "/cms/intro",
+      "permanent": true
+    },
     {
       "source": "/user-docs/content-manager/adding-content-to-releases",
       "destination": "/cms/features/releases#including-content-in-a-release",