Add a link to online docs

Author: rolandgeider

config/prod.env

@@ -11,8 +11,9 @@ TIME_ZONE=Europe/Berlin
 TZ=Europe/Berlin
 
 #
-# Consult the deployment section in the readme if you are running this behind a
-# reverse proxy with HTTPS enabled
+# If you get CSRF errors set your domain here
+# Consult the docs for more details:
+# https://wger.readthedocs.io/en/latest/production/docker.html#if-you-get-csrf-errors
 
 # CSRF_TRUSTED_ORIGINS=https://my.domain.example.com,https://118.999.881.119
 # X_FORWARDED_PROTO_HEADER_SET=True