title: Laravel: How to add 1 day to validation before rule
body: <p>How do I make the validation rule <code>before:end_date</code> +1 day? I.E. I want to make the rule before or including the end date. I know that the date is passed to the php strtotime function which takes '+1 days' as an argument but I can't get it to work.</p>
  
  <pre><code>protected $fillable = array('name','start_date', 'end_date', 'registration_start', 'registration_end');
  
  public static $rules = array(
      'registration_end' =&gt; 'required|date|before:end_date + 1 days'
  );
  </code></pre>