add index to readme

Author: senghoo

README.md

@@ -4,5 +4,35 @@
 
 Golang 设计模式的实例代码
 
-兼做研磨设计模式的读书笔记，把此书中的例子用Golang实现一遍。
+## 创建型模式
 
+* [简单工厂模式（Simple Factory）](https://github.com/senghoo/golang-design-pattern/tree/master/00_simple_factory)
+* [厂方法模式（Factory Method）](https://github.com/senghoo/golang-design-pattern/tree/master/04_factory_method)
+* [抽象工厂模式（Abstract Factory）](https://github.com/senghoo/golang-design-pattern/tree/master/05_abstract_factory)
+* [创建者模式（Builder）](https://github.com/senghoo/golang-design-pattern/tree/master/06_builder)
+* [原型模式（Prototype）](https://github.com/senghoo/golang-design-pattern/tree/master/07_prototype)
+* [单例模式（Singleton）](https://github.com/senghoo/golang-design-pattern/tree/master/02_adapter)
+
+## 结构型模式
+
+* [外观模式（Facade）](https://github.com/senghoo/golang-design-pattern/tree/master/01_facade)
+* [适配器模式（Adapter）](https://github.com/senghoo/golang-design-pattern/tree/master/02_adapter)
+* [代理模式（Proxy）](https://github.com/senghoo/golang-design-pattern/tree/master/09_proxy)
+* [组合模式（Composite）](https://github.com/senghoo/golang-design-pattern/tree/master/13_composite)
+* [享元模式（Flyweight）](https://github.com/senghoo/golang-design-pattern/tree/master/18_flyweight)
+* [装饰模式（Decorator）](https://github.com/senghoo/golang-design-pattern/tree/master/20_decorator)
+* [桥模式（Bridge）](https://github.com/senghoo/golang-design-pattern/tree/master/22_bridge)
+
+## 行为型模式
+
+* [中介者模式（Mediator）](https://github.com/senghoo/golang-design-pattern/tree/master/08_mediator)
+* [观察者模式（Observer）](https://github.com/senghoo/golang-design-pattern/tree/master/10_observer)
+* [命令模式（Command）](https://github.com/senghoo/golang-design-pattern/tree/master/11_command)
+* [迭代器模式（Iterator）](https://github.com/senghoo/golang-design-pattern/tree/master/12_iterator)
+* [模板方法模式（Template Method）](https://github.com/senghoo/golang-design-pattern/tree/master/14_template_method)
+* [策略模式（Strategy）](https://github.com/senghoo/golang-design-pattern/tree/master/15_strategy)
+* [状态模式（State）](https://github.com/senghoo/golang-design-pattern/tree/master/16_state)
+* [备忘录模式（Memento）](https://github.com/senghoo/golang-design-pattern/tree/master/17_memento)
+* [解释器模式（Interpreter）](https://github.com/senghoo/golang-design-pattern/tree/master/19_interpreter)
+* [职责链模式（Chain of Responsibility）](https://github.com/senghoo/golang-design-pattern/tree/master/21_chain_of_responsibility)
+* [访问者模式（Visitor）](https://github.com/senghoo/golang-design-pattern/tree/master/23_visitor)