code: func (o *InvitationManager) SetAcceptedByCode(code string) error {
  	qry := bson.M{
  		"code": code,
  	}
  	update := bson.M{
  		"$set": bson.M{
  			"status": RequestAccepted,
  		},
  	}
  	return o.collection.Update(qry, update)
  }
docs: // SetAcceptedByCode Sets an invite as "accepted"