Add minimal apps

shell.nix

@@ -0,0 +1,25 @@
+{
+  pkgs ? import <nixpkgs> {},
+}:
+let
+  ruby = pkgs.ruby_3_2;
+  llvm = pkgs.llvmPackages_16;
+  gcc = pkgs.gcc13;
+in llvm.stdenv.mkDerivation {
+  name = "sandbox-minimal.shell";
+
+  buildInputs = [
+    ruby
+
+    # for psych >= 5.1 pulled by rails 7.1
+    pkgs.libyaml.dev
+  ];
+
+
+  shellHook = ''
+    export RUBY_VERSION="$(ruby -e 'puts RUBY_VERSION.gsub(/\d+$/, "0")')"
+    export GEM_HOME="$(pwd)/vendor/bundle/ruby/$RUBY_VERSION"
+    export BUNDLE_PATH="$(pwd)/vendor/bundle"
+    export PATH="$GEM_HOME/bin:$PATH"
+  '';
+}