function GRIDDLE_SET_SORT(state, action) {
  // turn this into an array if it's not already
  const sortProperties = action.sortProperties.hasOwnProperty('length') ?
    action.sortProperties :
    [action.sortProperties];

  return state.set('sortProperties', new Immutable.fromJS(sortProperties));
}
Sets sort properties
@param {Immutable} state- Immutable previous state object
@param {Object} action - The action object to work with