Add gnome module

nixos/modules/des/gnome/default.nix

@@ -0,0 +1,21 @@
+{ config, lib, pkgs, ... }:
+
+{
+    services.xserver = {
+        enable = true;
+
+        # Enable the GNOME Desktop Environment.
+        displayManager.gdm.enable = true;
+        desktopManager.gnome.enable = true;
+
+    };
+
+    environment.gnome.excludePackages = (with pkgs; [
+        gnome-photos
+        gnome-tour
+        xterm
+    ]) ++ (with pkgs.gnome; [
+        gedit
+        gnome-terminal
+    ]);
+}