Add note regarding rake on headless mchines (#2076)

source/developers/website.markdown

@@ -36,6 +36,12 @@ Then you can work on the documentation:
 <p class='note'>
 It could be necessary that you run `rake generate` prior to `rake preview` for the very first preview.
 </p>
+<p class='note'>
+Site generated by `rake` is only available locally. If you are developing on a headless machine use port forwarding:
+```bash
+ssh -L 4000:localhost:4000 use_on_headless_machine@ip_of_headless_machine
+```
+</p>
 
 ### {% linkable_title Create a page %}