add comment to ease debugging

nginx.tmpl

@@ -86,6 +86,7 @@ server {
 
 {{ range $host, $containers := groupByMulti $ "Env.VIRTUAL_HOST" "," }}
 {{ $upstream_name := sha1 $host }}
+# {{ $host }}
 upstream {{ $upstream_name }} {
 {{ range $container := $containers }}
 	{{ $addrLen := len $container.Addresses }}