Drupal 7 settings.php to run on Heroku

settings.php

$url = parse_url(getenv('DATABASE_URL')); // Be sure to run [heroku config:set DATABASE_URL=mysql://db_username:db_password@amazon_rds_instance_name/db_name]
$databases['default']['default'] = array(
  // MySQLi uses the mysql driver.
  'driver' => $url['scheme'] == 'mysqli' ? 'mysql' : $url['scheme'],
  // Remove the leading slash to get the database name.
  'database' => substr(urldecode($url['path']), 1),
  'username' => urldecode($url['user']),
  'password' => isset($url['pass']) ? urldecode($url['pass']) : '',
  'host' => urldecode($url['host']),
  'port' => isset($url['port']) ? urldecode($url['port']) : '',
);