install gulp to process code

node_modules/undertaker/lib/task.js

@@ -0,0 +1,16 @@
+'use strict';
+
+function task(name, fn) {
+  if (typeof name === 'function') {
+    fn = name;
+    name = fn.displayName || fn.name;
+  }
+
+  if (!fn) {
+    return this._getTask(name);
+  }
+
+  this._setTask(name, fn);
+}
+
+module.exports = task;