Allow nix to manage agda

.envrc

@@ -0,0 +1,7 @@
+use_flake() {
+    watch_file flake.nix
+    watch_file flake.lock
+    eval "$(nix print-dev-env --profile "$(direnv_layout_dir)/flake-profile")"
+}
+
+use_flake

flake.nix

@@ -0,0 +1,18 @@
+{
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem
+    (system:
+    let pkgs = nixpkgs.legacyPackages.${system}; in {
+      devShell =
+        pkgs.mkShell {
+          buildInputs = 
+          with pkgs; [
+            emacs
+            agda
+          ];
+        };
+    });
+}
+