code: func (user *User) SaveSettings(allSettings interface{}) error {
  
  	serviceID := user.ctx.getServiceID()
  
  	_, err := user.ctx.db.C("users").UpsertId(user.ID, bson.M{"$set": bson.M{"settings." + serviceID: allSettings}, "$setOnInsert": bson.M{"createdat": time.Now()}})
  
  	if user.data == nil {
  		user.data = &userData{}
  	}
  	if user.data.Settings == nil {
  		user.data.Settings = make(map[string]interface{})
  	}
  	user.data.Settings[serviceID] = allSettings
  
  	return err
  }
docs: // SaveSettings save User's setting for service