function load(filename, callback) {
  parse(filename, function (err, result) {
    if (err) {
      // we should have bombed already, but
      utils.log.error(err);
      callback(err);
    }

    if (result.raw) {
      result.raw.forEach(add.bind(null, rules, 'ignore'));
    } else {
      result.ignore.forEach(add.bind(null, rules, 'ignore'));
      result.watch.forEach(add.bind(null, rules, 'watch'));
    }

    callback(null, rules);
  });
}
Loads a nodemon config file and populates the ignore
and watch rules with it's contents, and calls callback
with the new rules

@param  {String} filename
@param  {Function} callback