Add initial flake file.

flake.nix

@@ -0,0 +1,42 @@
+{
+  description = "NixOS Configuration";
+  inputs = rec {
+    nixpkgs.url = "github:/NixOS/nixpkgs/nixos-unstable";
+    nixpkgs-unstable.url = "github:/NixOS/nixpkgs/nixos-unstable";
+    nixpkgs-stable.url = "github:/NixOS/nixpkgs/nixos-22.11";
+    mailserver.url = "gitlab:/simple-nixos-mailserver/nixos-mailserver";
+    sops-nix = {
+      url = github:Mic92/sops-nix;
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+  outputs = { self, nixpkgs, mailserver, sops-nix, ... }@attrs: let
+    lib = nixpkgs.lib;
+    fn = import ./fn.nix { inherit lib; };
+    system = "x86_64-linux";
+    machineList = fn.lst { p = (toString ./machines); t = "directory"; b = false; };
+    configFiles = fn.lst { p = (toString ./config); b = true; };
+    pkgsFiles = fn.lst { p = (toString ./pkgs); b = true; };
+    serviceFiles = fn.lst { p = (toString ./services); b = true; };
+    nixosSystemFor = machine: {
+      name = machine;
+      value = let
+        machinePath = lib.concatStringsSep "/" [(toString ./.) "machines" machine];
+        machineFiles = fn.lst { p = machinePath; b = true; };
+      in nixpkgs.lib.nixosSystem {
+        inherit system;
+        specialArgs = attrs;
+        modules = [
+          (toString ./options/machine.nix)
+          sops-nix.nixosModules.sops
+        ] ++ machineFiles
+        ++ configFiles
+        ++ pkgsFiles
+        ++ serviceFiles;
+      };
+    };
+    result =  lib.listToAttrs (map nixosSystemFor ["Lilim"]);
+  in {
+    nixosConfigurations = lib.listToAttrs (map nixosSystemFor machineList);
+  };
+}