create(model) {
    if (!model.id && model.id !== 0) {
      model.id = guid();
      model.set(model.idAttribute, model.id);
    }

    this._setItem(this._itemName(model.id), this.serializer.serialize(model));
    this.records.push(model.id.toString());
    this.save();

    return this.find(model);
  }
Add a new model with a unique GUID, if it doesn't already have its own ID
@param {Model} model - The Backbone Model to save to LocalStorage
@returns {Model} The saved model