Write listeners statistics for a current song in case of an interrupting signal.

cmd/dwelling-radio/main.go

@@ -112,6 +112,7 @@ func main() {
 		switch <-sysSignal {
 		case os.Interrupt, syscall.SIGINT, syscall.SIGTERM, syscall.SIGABRT, syscall.SIGSEGV:
 			if currentSong.Artist != "" {
+				currentSong.Listeners, currentSong.MaxListeners = lstnrs.Reset()
 				if err := stats.Add(&currentSong); err != nil {
 					log.Println("failed to save a current song during a shutdown:", err)
 				}