extract gnome into module

nixos/common/modules/gnome/default.nix

@@ -0,0 +1,59 @@
+{ config, pkgs, lib, flat_hosts, ... }:
+with lib;
+let cfg = config.services.v.gnome;
+
+in {
+  options.services.v.gnome = { enable = mkEnableOption "v.gnome"; };
+
+  config = mkIf cfg.enable {
+    services.xserver.enable = true;
+    services.xserver.excludePackages = [ pkgs.xterm ];
+
+    home-manager.sharedModules = [
+      ./dconf.nix
+    ];
+
+    # Configure keymap in X11
+    services.xserver = {
+      layout = "us";
+      xkbVariant = "altgr-intl";
+    };
+
+    # Enable the GNOME Desktop Environment.
+    services.xserver.displayManager.gdm.enable = true;
+    services.xserver.desktopManager.gnome.enable = true;
+    services.udev.packages = with pkgs; [ gnome.gnome-settings-daemon ];
+    environment.gnome.excludePackages =
+      (with pkgs; [ gnome-photos gnome-tour gnome-connections ])
+      ++ (with pkgs.gnome; [
+        atomix # puzzle game
+        epiphany # web browser
+        geary # email reader
+        gedit # text editor
+        gnome-calendar
+        gnome-clocks
+        gnome-contacts
+        gnome-maps
+        gnome-music
+        gnome-notes
+        gnome-terminal
+        gnome-weather
+        hitori # sudoku game
+        iagno # go game
+        simple-scan # document scanner
+        tali # poker game
+        totem # video player
+      ]);
+
+    # Services required for gnome
+    programs.dconf.enable = true;
+    services.dbus.enable = true;
+    services.udisks2.enable = true;
+
+    # Extra gnome packages
+    environment.systemPackages = with pkgs; [
+      gnome.gnome-tweaks
+      gnome.gnome-boxes
+    ];
+  };
+}