"Web Development with Go" Mangodb insert struct data

Learning data persistence.

package main

import (
	"fmt"
	"log"
	"time"

	"gopkg.in/mgo.v2"
	"gopkg.in/mgo.v2/bson"
)

type Category struct {
	Id          bson.ObjectId `bson:"_id,omitempty"`
	Name        string
	Description string
}

func main() {
	mongoDialInfo := &mgo.DialInfo{
		Addrs:    []string{"localhost"},
		Timeout:  5 * time.Second,
		Database: "taskdb",
		Username: "root",
		Password: "123456",
	}
	session, err := mgo.DialWithInfo(mongoDialInfo)

	if err != nil {
		panic(err)
	}

	defer session.Close()

	session.SetMode(mgo.Monotonic, true)
	c := session.DB("taskdb").C("categories")

	doc := Category{
		bson.NewObjectId(),
		"Open Source",
		"Tasks for open-source projects",
	}

	err = c.Insert(&doc)
	if err != nil {
		log.Fatal(err)
	}

	err = c.Insert(
		&Category{
			bson.NewObjectId(),
			"R & D",
			"R & D Tasks",
		},
		&Category{
			bson.NewObjectId(),
			"Project",
			"Project Tasks",
		})
	var count int
	count, err = c.Count()
	if err != nil {
		log.Fatal(err)
	} else {
		fmt.Printf("%d records inserted.", count)
	}
}