Update README.md - add second config link

Author: jessebot

README.md

@@ -33,10 +33,14 @@ helm install --namespace pixelfed --create-namespace pixelfed/pixelfed --values
 
 ## Notes
 
-You can find the general Pixelfed configuration docs here:
+You can find some of the general Pixelfed configuration docs here:
 
 https://docs.pixelfed.org/running-pixelfed/installation.html
 
+But you'll find additional configuration here:
+
+https://github.com/pixelfed/pixelfed/blob/dev/.env.docker
+
 ### Creating your first user
 
 ```console