all index.md files renamed to README.md for more compatibility with github

bridge/README.md

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+---
+layout: pattern
+title: Bridge
+folder: bridge
+permalink: /patterns/bridge/
+categories: Structural
+tags:
+ - Java
+ - Gang Of Four
+ - Difficulty-Intermediate
+---
+
+## Also known as
+Handle/Body
+
+## Intent
+Decouple an abstraction from its implementation so that the two can
+vary independently.
+
+![alt text](./etc/bridge.png "Bridge")
+
+## Applicability
+Use the Bridge pattern when
+
+* you want to avoid a permanent binding between an abstraction and its implementation. This might be the case, for example, when the implementation must be selected or switched at run-time.
+* both the abstractions and their implementations should be extensible by subclassing. In this case, the Bridge pattern lets you combine the different abstractions and implementations and extend them independently
+* changes in the implementation of an abstraction should have no impact on clients; that is, their code should not have to be recompiled.
+* you have a proliferation of classes. Such a class hierarchy indicates the need for splitting an object into two parts. Rumbaugh uses the term "nested generalizations" to refer to such class hierarchies
+* you want to share an implementation among multiple objects (perhaps using reference counting), and this fact should be hidden from the client. A simple example is Coplien's String class, in which multiple objects can share the same string representation.
+
+## Credits
+
+* [Design Patterns: Elements of Reusable Object-Oriented Software](http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-Oriented/dp/0201633612)