func (store BookmarkStore) Create(b *Bookmark) error {
	b.ID = bson.NewObjectId()
	err := store.C.Insert(b)
	return err
}
Create inserts the value of struct Bookmark into collection.
package main
import (
	"time"
	"gopkg.in/mgo.v2"
	"gopkg.in/mgo.v2/bson"
)
type Bookmark struct {
	ID                          bson.ObjectId `bson:"_id,omitempty"`
	Name, Description, Location string
	Priority                    int  
	CreatedOn                   time.Time
	Tags                        []string
}
type BookmarkStore struct {
	C *mgo.Collection
}