title: Laravel: validate an integer field that needs to be greater than another
body: <p>I have two fields that are optional only if both aren't present:</p>
  
  <pre><code>$rules = [
    'initial_page' =&gt; 'required_with:end_page|integer|min:1|digits_between: 1,5',
    'end_page' =&gt; 'required_with:initial_page|integer|min:2|digits_between:1,5'
  ]; 
  </code></pre>
  
  <p>Now, <code>end_page</code> needs to be greater than <code>initial_page</code>. How include this filter?</p>