Add media upload capability to contributor on WordPress

contributor-upload.php

<?php
//Do not add the line above

if ( current_user_can('contributor') && !current_user_can('upload_files') )
//checks if the current user is a contributor 
  add_action('admin_init', 'allow_contributor_uploads');
  function tayo_allow_contributor_uploads() {
    $contributor = get_role('contributor');
    $contributor->add_cap('upload_files');
  }