init Adapter

adapter/README.md

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+## Adapter
+
+Convert the interface of a class into another interface clients expect.
+Adapter lets classes work together that couldn't otherwise because of
+incompatible interfaces. 
+
+### When to use
+
+* you want to use an existing class, and its interface does not match the one you need
+* you want to create a reusable class that cooperates with classes that don't necessarily have compatible interfaces
+