feat: add nixos module for rrv-sh website

flake.nix

@@ -27,5 +27,6 @@
           default = pkgs.callPackage ./nix/package.nix { };
         }
       );
+      nixosModules.default = import ./nix/modules/nixos.nix;
     };
 }

nix/modules/nixos.nix

@@ -0,0 +1,51 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+let
+  inherit (builtins) toString;
+  inherit (lib) mkOption mkEnableOption mkIf;
+  inherit (lib.types) port str;
+  cfg = config.services.rrv-sh;
+  package = pkgs.callPackage ../package.nix { };
+in
+{
+  options.services.rrv-sh = {
+    enable = mkEnableOption "";
+    port = mkOption {
+      type = port;
+      default = 2309;
+    };
+    user = mkOption {
+      type = str;
+      default = "rrv-sh";
+    };
+    group = mkOption {
+      type = str;
+      default = "rrv-sh";
+    };
+  };
+  config = mkIf cfg.enable {
+    users.users.rrv-sh = mkIf (cfg.user == "rrv-sh") {
+      inherit (cfg) group;
+      isSystemUser = true;
+      description = "rrv.sh server user";
+    };
+    users.groups.rrv-sh = mkIf (cfg.user == "rrv-sh") { };
+    systemd.services.rrv-sh = {
+      description = "the rrv.sh website";
+      after = [ "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+      serviceConfig = {
+        Type = "simple";
+        Restart = "on-failure";
+        RestartSec = "5s";
+        User = cfg.user;
+        Group = cfg.group;
+        ExecStart = "${pkgs.live-server}/bin/live-server -p ${toString cfg.port} ${package}";
+      };
+    };
+  };
+}