code: function(pattern, options, cb) {
        if (typeof options === 'function') {
          return this.readdir(pattern, {}, options);
        }
  
        this.emit('read');
        this.setPattern(pattern, options);
        this.iteratorAsync(this.pattern.base, function (err) {
          if (err) return cb(err);
  
          this.emit('end', this.files);
          cb.call(this, null, this.files);
        }.bind(this));
        return this;
      }
docs: Asynchronously glob files or directories that match
  the given `pattern`.
  
  ```js
  var glob = require('glob-fs')({ gitignore: true });
  
  glob.readdir('*.js', function (err, files) {
  //=> do stuff with `files`
  });
  ```
  
  @name .readdir
  @param  {String} `pattern` Glob pattern
  @param  {Object} `options`
  @param  {Function} `cb` Callback
  @api public