code: func (service *Service) initLoginModels() {
  	index := mgo.Index{
  		Key:      []string{"sessionkey"},
  		Unique:   true,
  		DropDups: false,
  	}
  
  	db.EnsureIndex(mongoLoginCollectionName, index)
  
  	automaticExpiration := mgo.Index{
  		Key:         []string{"createdat"},
  		ExpireAfter: time.Second * 60 * 10,
  		Background:  true,
  	}
  	db.EnsureIndex(mongoLoginCollectionName, automaticExpiration)
  
  }
docs: //initLoginModels initialize models in mongo