Add staging environment info

Signed-off-by: Morris Jobke <hey@morrisjobke.de>

README.md

@@ -10,3 +10,13 @@ hugo server
 
 and open [http://localhost:1313/](http://localhost:1313/) in the browser.
 
+
+# Staging environment
+
+Currently there is a staging environment set up at [https://staging.weasel.rocks](https://staging.weasel.rocks), which serves the normal Wordpress powered website. Additionally special URLs are instead served from this hugo website. Currently those are:
+
+* `/css`
+* `/static-assets`
+* [`/changelog`](https://staging.weasel.rocks/changelog/)
+
+This should be a showcase on how well it all works together during the step by step migration from Wordpress to Hugo. Once the state of the staging environment is ready for production we will move it over to the real website and monitor it.