mailThreadCache

type MailCache struct {
	MailId    bson.ObjectId `bson:"_id"`
	Read      bool          `bson:"read"`
	From      bson.ObjectId `bson:"from"`
	TimeStamp time.Time     `bson:"time"`
	Subject   string        `bson:"subject"`
}

type MailThreadCache struct {
	ThreadId   bson.ObjectId `bson:"_id"` // this is the primary key
	MailCaches []MailCache   `bson:"mailCache"`
}