Added a deck of cards functionality

lib/Shuffle.hs

@@ -0,0 +1,24 @@
+module Shuffle (
+    shuffle
+) where
+
+import Data.List
+import System.Random
+
+seed = 20
+
+-- Shuffle a list of values.
+shuffle :: [a] -> [a]
+shuffle l = map (l !!) $ generateIndices $ length l
+
+-- Generate indices to map the elements of a list over so that they 
+-- are randomly shuffled.
+generateIndices :: Int -> [Int]
+generateIndices size = take size uniqueList
+    where randomList = randomRs (0, size - 1) randomGen
+          uniqueList = nub randomList
+
+-- Generate a random generator
+-- TODO Écht random maken?
+randomGen :: StdGen
+randomGen = mkStdGen seed