Change flake.nix to allow different nixpkgs versions

hosts/default/system.nix

@@ -0,0 +1,39 @@
+# Edit this configuration file to define what should be installed on
+# your system. Help is available in the configuration.nix(5) man page, on
+# https://search.nixos.org/options and in the NixOS manual (`nixos-help`).
+
+{ 
+    lib,
+    config,
+    pkgs,
+    ...
+}: {
+    nix = {
+        settings = {
+            experimental-features = "nix-command flakes";
+        };
+    };
+
+    # Use the systemd-boot EFI boot loader.
+    boot.loader.systemd-boot.enable = true;
+    boot.loader.efi.canTouchEfiVariables = true;
+
+    # Set your time zone.
+    time.timeZone = "America/Chicago";
+
+    # Select internationalisation properties.
+    i18n.defaultLocale = "en_US.UTF-8";
+
+    # Define a user account.
+    users.users.eesim = {
+        isNormalUser = true;
+        extraGroups = [ "wheel" ];
+    };
+
+    # Do NOT change this value unless you have manually inspected all the changes it would make to your configuration,
+    # and migrated your data accordingly.
+    # For more information, see `man configuration.nix` or https://nixos.org/manual/nixos/stable/options#opt-system.stateVersion .
+    system.stateVersion = "23.11"; # Did you read the comment?
+
+}
+