refactored nixos directory & updated README

nixos/internationalisation.nix

@@ -0,0 +1,38 @@
+{ pkgs, ... }:
+
+{
+  # Select internationalisation properties.
+  services.xserver = {
+    layout = "us,ua,ru";
+    xkbOptions = "grp:alt_shift_toggle";
+  };
+  
+  i18n.supportedLocales = [
+    "en_US.UTF-8/UTF-8"
+    "uk_UA.UTF-8/UTF-8"
+    "ru_RU.UTF-8/UTF-8"
+  ];
+  
+  i18n.defaultLocale = "en_US.UTF-8";
+
+  i18n.extraLocaleSettings = {
+    LC_ADDRESS = "en_US.UTF-8";
+    LC_IDENTIFICATION = "en_US.UTF-8";
+    LC_MEASUREMENT = "en_US.UTF-8";
+    LC_MONETARY = "en_US.UTF-8";
+    LC_NAME = "en_US.UTF-8";
+    LC_NUMERIC = "en_US.UTF-8";
+    LC_PAPER = "en_US.UTF-8";
+    LC_TELEPHONE = "en_US.UTF-8";
+    LC_TIME = "en_US.UTF-8";
+  };
+
+  environment.systemPackages = with pkgs; [
+    nuspell
+    hyphen
+    hunspell
+    hunspellDicts.en_US
+    hunspellDicts.uk_UA
+    hunspellDicts.ru_RU
+  ];
+}