add haskell programming template

modules/programming/haskell.nix

@@ -0,0 +1,8 @@
+{ ... }: {
+
+  # Binary Cache for Haskell.nix
+  nix.settings.trusted-public-keys =
+    [ "hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ=" ];
+  nix.settings.substituters = [ "https://cache.iog.io" ];
+
+}