code: function readFiles (filepaths, callback) {
    async.map(filepaths, readFile.bind(this), function (err, files) {
  
      if (err) callback(err);
  
      callback(null, files);
    });
  }
docs: Read files
  @param {Array.<String>} filepaths
  @param {Function.<Error, Array.<Object.<DittoFile>>>} callback