Update example.nginx.conf

Updated the location block for "/api/config" to point directly to the node.js server @ localhost:3000

docs/example.nginx.conf

@@ -66,9 +66,12 @@ server {
         rewrite ^/customize/(.*)$ $1 break;
         try_files /customize/$uri /customize.dist/$uri;
     }
+
     location = /api/config {
-        default_type text/javascript;
-        rewrite ^.*$ /customize/api/config break;
+        proxy_pass http://localhost:3000;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header Host $host;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
         }
         
     location ^~ /blob/ {