added whole system from ola4doc

sys/node_modules/es5-ext/array/#/group.js

@@ -0,0 +1,23 @@
+// Inspired by Underscore's groupBy:
+// http://documentcloud.github.com/underscore/#groupBy
+
+'use strict';
+
+var callable = require('../../object/valid-callable')
+  , value    = require('../../object/valid-value')
+
+  , forEach = Array.prototype.forEach, apply = Function.prototype.apply;
+
+module.exports = function (cb/*, thisArg*/) {
+	var r;
+
+	(value(this) && callable(cb));
+
+	r = {};
+	forEach.call(this, function (v) {
+		var key = apply.call(cb, this, arguments);
+		if (!r.hasOwnProperty(key)) r[key] = [];
+		r[key].push(v);
+	}, arguments[1]);
+	return r;
+};