How I can encode JSON with multiple elements in Go Lang

I need consultation or sample code how I can send to customer multiple elements in JSON. Thank you!

I need next JSON structure:

{{"id":123,"first_name":"Demo","last_name":"User","time":"2017-07-03T16:36:41.4101847Z","count":1,"payout":"839`"},{"id":124,"first_name":"Demo","last_name":"User1","time":"2017-07-03T16:36:41.4101847Z","count":1,"payout":"839`"},{"id":125,"first_name":"Demo","last_name":"User2","time":"2017-07-03T16:36:41.4101847Z","count":1,"payout":"839`"}}

Here you are.

package main

import (
	"bytes"
	"encoding/json"
	"io"
	"log"
	"net/http"
	"os"
	"time"
)

type Elememt struct {
	ID int `json:"id"`
	FirstName string `json:"first_name"`
	LastName string `json:"last_name"`
	Time time.Time `json:"time"`
	Count int `json:"count"`
	Payout string `json:"payout"`
}

func main() {
	elements := []Elememt {
		{
			ID: 1,
			FirstName: "Dmitriy",
			LastName: "Groschovskiy",
			Time: time.Now(),
			Count: 1,
			Payout: "200",
		},
		{
			ID: 2,
			FirstName: "Yasuhiro",
			LastName: "Matsumoto",
			Time: time.Now(),
			Count: 2,
			Payout: "150",
		},
	}

	var buf bytes.Buffer
	err := json.NewEncoder(&buf).Encode(elements)
	if err != nil {
		log.Fatal(err)
	}
	req, err := http.NewRequest("POST", "http://httpbin.org/post", &buf)
	if err != nil {
		log.Fatal(err)
	}
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		log.Fatal(err)
	}
	defer resp.Body.Close()

	io.Copy(os.Stdout, resp.Body)
}