add support for SFTP subsystem mode

Fixes #204

logger/journald.go

@@ -0,0 +1,14 @@
+// +build linux
+
+package logger
+
+import (
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/journald"
+)
+
+// InitJournalDLogger configures the logger to write to journald
+func InitJournalDLogger(level zerolog.Level) {
+	logger = zerolog.New(journald.NewJournalDWriter()).Level(level)
+	consoleLogger = zerolog.Nop()
+}