document: update

README.md

@@ -1,10 +1,44 @@
 # appConfig
 
+[![Build Status](https://drone.io/github.com/kyokomi/appConfig/status.png)](https://drone.io/github.com/kyokomi/appConfig/latest)
+[![Coverage Status](https://img.shields.io/coveralls/kyokomi/appConfig.svg)](https://coveralls.io/r/kyokomi/appConfig?branch=master)
+
 =========
 
 homedir read write to app config file for golang ( Go )
 
-## Usage
+## Example
+
+[source](https://github.com/kyokomi/appConfig/blob/master/example/main.go)
+
+```go
+package main
+
+import (
+	"github.com/kyokomi/appConfig"
+	"bytes"
+	"log"
+	"fmt"
+)
+
+func main() {
+
+	accessToken := "aaaaaaaaaaaaaaaaaaaaa"
+
+	c := appConfig.NewAppConfig("goSampleApp")
+	err := c.WriteAppConfig(bytes.NewBufferString(accessToken).Bytes())
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	data, err := c.ReadAppConfig()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	fmt.Println(string(data))
+}
+```
 
 ## Install