Update lighttpd.conf.debian

Allow for password protection (or other user-initiated options) without clobbering already chosen user options.

advanced/lighttpd.conf.debian

@@ -12,6 +12,7 @@
 server.modules = (
 	"mod_access",
 	"mod_accesslog",
+	"mod_auth",
 	"mod_expire",
 	"mod_compress",
 	"mod_redirect",
@@ -59,3 +60,6 @@ $HTTP["url"] =~ "^(?!/admin)/.*" {
     # rewrite only js requests
     url.rewrite = ("(.*).js" => "pihole/index.js")
 }
+
+# Add user chosen options held in external file
+include_shell "cat external.conf 2>/dev/null"