Added backup machinery

backup.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+	"qurl/storage"
+	"time"
+	"fmt"
+	"path"
+	"os"
+)
+
+func manageBackup(stor storage.Storage, dir string, interval int){
+	for {
+		time.Sleep(time.Duration(interval) * time.Second)
+		fname := fmt.Sprintf("qurl-%s.backup",
+			time.Now().Format("20060102150405"))
+
+		err := stor.Backup(path.Join(dir, fname))
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Backup failure: %s\n", err.Error())
+		}
+	}
+}