public function rules()
{
$validationRule = [];
$validationRule['name'] = 'required|max:255';
if ($this->getMethod() == 'POST') {
$validationRule['slug'] = 'required|max:255|alpha_dash|unique:categories';
}
if ($this->getMethod() == 'PUT') {
$validationRule['slug'] = 'required|max:255|alpha_dash';
}
return $validationRule;
}