home: create 'modules/home' folder

Consolidating all modules under the same path, to clear out the
top-level directory.

modules/home/gdb/default.nix

@@ -0,0 +1,38 @@
+{ config, lib, pkgs, ... }:
+let
+  cfg = config.my.home.gdb;
+in
+{
+  options.my.home.gdb = with lib; {
+    enable = my.mkDisableOption "gdb configuration";
+
+    rr = {
+      enable = my.mkDisableOption "rr configuration";
+
+      package = mkOption {
+        type = types.package;
+        default = pkgs.rr;
+        defaultText = literalExample "pkgs.rr";
+        description = ''
+          Package providing rr
+        '';
+      };
+    };
+  };
+
+  config = lib.mkIf cfg.enable (lib.mkMerge [
+    {
+      home.packages = with pkgs; [
+        gdb
+      ];
+
+      xdg.configFile."gdb/gdbinit".source = ./gdbinit;
+    }
+
+    (lib.mkIf cfg.rr.enable {
+      home.packages = [
+        cfg.rr.package
+      ];
+    })
+  ]);
+}