install gulp to process code

node_modules/arr-union/index.js

@@ -0,0 +1,30 @@
+/*!
+ * arr-union <https://github.com/jonschlinkert/arr-union>
+ *
+ * Copyright (c) 2014-2015, Jon Schlinkert.
+ * Licensed under the MIT License.
+ */
+
+'use strict';
+
+module.exports = function union(arr) {
+  var len = arguments.length;
+  var res = [], i = 0;
+
+  while (len--) {
+    var arg = arrayify(arguments[i++]);
+
+    for (var j = 0; j < arg.length; j++) {
+      var ele = arg[j];
+
+      if (res.indexOf(ele) === -1) {
+        res.push(ele);
+      }
+    }
+  }
+  return res;
+};
+
+function arrayify(val) {
+  return Array.isArray(val) ? val : [val];
+}