feat: add ruby

Modules/System/Programming-Tools/default.nix

@@ -7,5 +7,6 @@
     ./lua.nix
     ./python.nix
     ./rust.nix
+    ./ruby.nix
   ];
 }

Modules/System/Programming-Tools/ruby.nix

@@ -0,0 +1,46 @@
+# Ruby (System Module)
+#
+# Provides:
+#   - Ruby (standard interpreter)
+#   - JRuby (Ruby on the JVM)
+#   - Bundler (Ruby package manager, optional)
+#
+# Options:
+#   - enable   → Enable Ruby system module (default: false)
+#   - bundler  → Install Bundler alongside Ruby (default: follows `enable`)
+#
+# Examples:
+#   nyx-module.system.ruby.enable = true;
+#   nyx-module.system.ruby.bundler = false; # disable Bundler explicitly
+#
+
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.nyx-module.system.ruby;
+in
+{
+  options.nyx-module.system.ruby = {
+    enable = lib.mkEnableOption "Enable Ruby (system module)";
+
+    bundler = lib.mkOption {
+      type = lib.types.bool;
+      default = cfg.enable; # follows Ruby enable by default
+      description = ''
+        Install Bundler with Ruby.
+        Defaults to the same value as `enable`.
+      '';
+      example = true;
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    environment.systemPackages =
+      with pkgs;
+      [
+        ruby
+        jruby
+      ]
+      ++ lib.optional cfg.bundler bundler;
+  };
+}