update readme

Author: zbindenren

README.md

@@ -1,21 +1,3 @@
 # king
 
-Use as follows:
-
-```go
-func main() {
-	v := info.NewGoReleaser(version, commit, date)
-	cli := cmd.CLI{}
-	app := kong.Parse(&cli, king.DefaultOptions(
-		king.Config{
-			Name:        "appname",
-			Description: "A description",
-			Version:     v.String(),
-		},
-	)...)
-	defer cancel()
-	if err := app.Run(&cli.Globals, l); err != nil {
-		log.Fatal(err)
-	}
-}
-```
+See [_example/main.go](../master/_example/main.go) on how to use it.