code: function getUser (username, password, callback = null) {
  	/* istanbul ignore else */
  	if (callback == null) {
  		return new Promise(function (resolve) {
  			function done (_, data) {
  				resolve(data);
  			}
  			getuser(username, password, done);
  		});
  	} else {
  		getuser(username, password, callback);
  	}
  }
docs: This version return a {Promise} so it can be used with await
  @param {String} username - Data that represents the username field in the target model.
  @param {String} passowrd - Unencrypted data that represents the username field in the target model.
  @param {Function} [callback] - Skip this value to return a Promise
  @return {Promise<AuthModel>|undefined} - if callback is not set it will return a promise