Add Nix flake configuration

modules/editors/neovim.nix

@@ -0,0 +1,18 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+with lib.my;
+let cfg = config.modules.editors.neovim;
+in {
+  options.modules.editors.neovim = {
+    enable = mkBoolOpt false;
+  };
+
+  config = mkIf cfg.enable {
+    home.programs.neovim = {
+      enable = true;
+      vimAlias = true;
+      vimdiffAlias = true;
+    };
+  };
+}