wp-config.php

if (null !== getenv("DATABASE_URL")) {
  $db = parse_url(getenv("DATABASE_URL"));
  define("DB_NAME", trim($db["path"],"/"));
  define("DB_USER", $db["user"]);
  define("DB_PASSWORD", $db["pass"]);
  define("DB_HOST", $db["host"]);
  define('DB_CHARSET', 'utf8');
  define('DB_COLLATE', '');
} else {
  die("Your heroku DATABASE_URL does not appear to be correctly specified.");
}