store other data in signup function Laravel 5.3 - php

Question

I'm modifying the signup function that store user's data( email and password). I wish to include more data such as phone number, name and national ID. I tried but in mysql database it doesn't show anything. Here is what I have done :
public function signup(Request $request)
{
$credentials = $request->only([
'national_id' ,
'name' ,
'phone',
]);
$validator = Validator::make($credentials, [
'name' => 'required',
'email' => 'sometimes|email|unique:users',
'password' => 'sometimes|min:6|confirmed',
'password_confirmation' => 'sometimes|min:3',
'national_id' => 'required','unique:national_id',
]);
if ($validator->fails()) {
throw new ValidationHttpException($validator->errors()->all());
}
try {
$user = $this->users->create($request->except('roles', 'permissions'));
if (!$user->id) {
return $this->response->error('could_not_create_user', 500);
}
$hasToReleaseToken = Config::get('boilerplate.signup_token_release');
if ($hasToReleaseToken) {
$user->national_id = $request->national_id;
return $this->login($request);
}
return $this->response->created();
} catch (\Exception $e) {
return $this->response->error($e->getMessage(), 500);
}
}
when I dd($request->national_id it shows me the national_id data in postman, but in my database it's NULL.