code: function _store(dest, source, callback) {
    fs.writeFile(dest, JSON.stringify(source), callback);
  }
docs: Stores json-compatible object on file system at provided path as
  a json file.
  @param {String} dest - File system path of the new file.
  @param {Object} source - The object to be stored.
  @param {Function} callback - Callback that expects only a possible error.