Update log messages on shutdown

background.go

@@ -1,6 +1,7 @@
 package asynq
 
 import (
+	"fmt"
 	"os"
 	"os/signal"
 	"sync"
@@ -49,6 +50,7 @@ func (bg *Background) Run(handler TaskHandler) {
 	sigs := make(chan os.Signal, 1)
 	signal.Notify(sigs, os.Interrupt, os.Kill)
 	<-sigs
+	fmt.Printf("\nStarting graceful shutdown...\n")
 }
 
 // starts the background-task processing.