refactor rice into config

common/nix/tools.nix

@@ -0,0 +1,21 @@
+{ pkgs, inputs, ... }:
+{
+
+  environment.systemPackages = builtins.attrValues {
+    inherit (pkgs)
+      home-manager
+      cachix
+      nixfmt-rfc-style
+      ;
+    inherit (inputs.nil.packages.${pkgs.system}) nil;
+  };
+  hm.imports = [
+    inputs.nix-index-database.hmModules.nix-index
+  ];
+  imports = [
+    inputs.nix-index-database.nixosModules.nix-index
+  ];
+  programs.nix-index-database.comma.enable = true;
+  programs.nix-index.enableZshIntegration = false;
+  programs.nix-index.enableBashIntegration = false;
+}