update(model) {
    this._setItem(this._itemName(model.id), this.serializer.serialize(model));

    const modelId = model.id.toString();

    if (!contains(this.records, modelId)) {
      this.records.push(modelId);
      this.save();
    }
    return this.find(model);
  }
Update an existing model in LocalStorage
@param {Model} model - The model to update
@returns {Model} The updated model