Add music support

src/Music.hs

@@ -0,0 +1,9 @@
+{-# LANGUAGE TemplateHaskell #-}
+module Music
+  where
+import qualified SDL.Mixer as Mix
+import qualified Data.IntMap as IM
+
+data MusicData = MusicData
+    { _loadedMusic   :: IM.IntMap Mix.Music
+    }