Add the haskell book

Haskell-book/11/TooMany.hs

@@ -0,0 +1,16 @@
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE FlexibleInstances #-}
+module TooMany where
+
+newtype Goats = Goats Int deriving (Eq, Show, TooMany)
+
+newtype Cows = Cows Int deriving (Eq, Show)
+
+class TooMany a where
+    tooMany :: a -> Bool
+
+instance TooMany Int where
+    tooMany n = n > 42
+
+instance TooMany (Int, String) where
+    tooMany (n, _) = n > 42