added a hash generator

id.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"crypto/md5"
+	"fmt"
+	"io"
+	"time"
+)
+
+type IdGenerator struct {
+	id chan int64
+}
+
+func NewIdGenerator() *IdGenerator {
+	g := IdGenerator{}
+	g.id = make(chan int64)
+	go func() {
+        var i int64
+		for i = 0; ; i++ {
+			g.id <- i
+		}
+	}()
+	return &g
+}
+
+func (id *IdGenerator) Hash() string {
+	h := md5.New()
+	ns := time.Now().UnixNano() + <-id.id
+	io.WriteString(h, fmt.Sprintf("%d", ns))
+	return fmt.Sprintf("%x", h.Sum(nil))
+}