code: function (identifier, values) {
              var self = this;
  
              return this.findByIdentifier(identifier).then(function (record) {
                  if (record) {
                      return record;
                  } else {
                      return self.create(values);
                  }
              });
          }
docs: Using an identifier, find and update, or create a new instance if none exists
  using the values provided. Returns a waterline (bluebird) promise with the record
  created or updated.
  
  @param {string} identifier
  @param {Object} values
  @returns {Deferred}