chore: example

Author: zenghur

README.md

@@ -8,5 +8,29 @@ Roc is a key-value memory cache.
 * Quick GC
 
 ## Usage
+```go
+package main
+
+import (
+	"fmt"
+	"github.com/xiaojiaoyu100/roc"
+	"time"
+)
+
+func main() {
+	cache, err := roc.New()
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	if err := cache.Set("myfirstkey", "123", time.Second*3); err != nil {
+		fmt.Println(err)
+		return
+	}
+	fmt.Println(cache.Get("myfirstkey"))
+	fmt.Println(cache.Del("myfirstkey"))
+	fmt.Println(cache.Get("myfirstkey"))
+}
+```