the readme.md is wrong with the usage

[jasonhcb]

when i use the docs usage

$form->daterangepicker('date_range', 'Date range');

it's wrong and return a error :

 implode(): Invalid arguments passed

and when i try next usage like

$form->daterangepicker(['created_at', 'updated_at'], 'Date range');

and it works .it's the bad readme.md