code: function (callback) {
  					if (!handlebarsMatcher.test(file)) {
  						return callback();
  					}
  
  					render(file, metadata, function (err, res) {
  						if (err) return callback(err);
  						// safety check to prevent file deletion in case filename doesn't change
  						if (file === res) return callback();
  						// safety check to prevent overwriting another file
  						if (files[res]) return callback(`Cannot rename file ${file} to ${res}. A file with that name already exists.`);
  
  						// add entry for interpolated file name
  						files[res] = files[file];
  						// delete entry for template file name
  						delete files[file];
  						callback();
  					});
  				}
docs: interpolate the file name