code: function (patternFolder, cb) {
      // read pattern folder
      fs.readdir(patternFolder, function (err, contents) {
        // check for errors
        if (err !== null && err.code === 'ENOENT') {
          grunt.log.error('Cannot find patterns folder:', patternFolder);
          cb('Cannot find patterns folder: ' + patternFolder);
          return;
        }
  
        // list all pattern files (that end with .html)
        var files = [];
        contents.forEach(function (content) {
          if (content.substr(-5) === '.html') {
            files.push(content);
          }
        });
        // handle all the found pattern files
        handleFiles(patternFolder, files, cb);
      });
    }
docs: reads all the patterns from the folder