func signalHandler() {
	sigchan := make(chan os.Signal, 1)
	signal.Notify(sigchan, os.Interrupt)
	signal.Notify(sigchan, syscall.SIGTERM)
	<-sigchan
	defer os.Exit(0)
	err := fs.Shutdown()
	if err != nil {
		msg := fmt.Sprintf("shutdown error: %s", err.Error())
		fmt.Println(msg)
		os.Exit(1)
	}
}
===========================================================================
OS Signal Handlers
===========================================================================
package main
import (
	"fmt"
	"os"
	"os/signal"
	"syscall"
	"github.com/bbengfort/memfs"
	"github.com/urfave/cli"
)
var fs *memfs.FileSystem