<?php

$regras = array(
    array(
        'field' => 'cpf',
        'label' => 'CPF',
        'rules' => 'required'
    ),
    array(
        'field' => 'senha',
        'label' => 'SENHA',
        'rules' => 'required|trim'
    ),
);
print_r($regras);

$regras[] = array(
    'field' => 'nome',
    'label' => 'NOME',
    'rules' => 'required|trim'
);
print_r($regras);