wait for process to terminate

```
func shutdown(c chan os.Signal, done chan bool) {
	sig := <-c
	fmt.Println("SHUTDOWN", sig)
	fmt.Println("shutting down ...")
	time.Sleep(time.Second * 1)
	fmt.Println("... ok")

	done <- true
}
```

currently the process gets something like 1 millisecond to terminate, it prints "shutting down ...", but it's terminated