Add table of contents

readme.md

@@ -16,6 +16,23 @@ A topic that can easily make anyone's mind wobble. Here I try to make them stick
 
 <sub>Check out my [other project](http://roadmap.sh) and say "hi" on [Twitter](https://twitter.com/kamranahmedse).</sub>
 
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+|[Creational Design Patterns](#creational-design-patterns)|[Structural Design Patterns](#structural-design-patterns)|[Behavioral Design Patterns](#behavioral-design-patterns)|
+|:-|:-|:-|
+|[Simple Factory](#-simple-factory)|[Adapter](#-adapter)|[Chain of Responsibility](#-chain-of-responsibility)|
+|[Factory Method](#-factory-method)|[Bridge](#-bridge)|[Command](#-command)|
+|[Abstract Factory](#-abstract-factory)|[Composite](#-composite)|[Iterator](#-iterator)|
+|[Builder](#-builder)|[Decorator](#-decorator)|[Mediator](#-mediator)|
+|[Prototype](#-prototype)|[Facade](#-facade)|[Memento](#-memento)|
+|[Singleton](#-singleton)|[Flyweight](#-flyweight)|[Observer](#-observer)|
+||[Proxy](#-proxy)|[Visitor](#-visitor)|
+|||[Strategy](#-strategy)|
+|||[State](#-state)|
+|||[Template Method](#-template-method)|
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 Introduction
 =================