add nix flake

.envrc

@@ -0,0 +1 @@
+use flake

flake.lock

@@ -0,0 +1,25 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1676790509,
+        "narHash": "sha256-W9uWAWokgS8US8rJf79qBLS2M+ZgIscfoz+KsNE7VGQ=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "a1291d0d020a200c7ce3c48e96090bfa4890a475",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,20 @@
+{
+  description = "Doggo flake";
+
+  outputs = { self, nixpkgs }:
+    let pkgs = nixpkgs.legacyPackages.x86_64-linux;
+    in {
+      # packages.x86_64-linux.hello = pkgs.hello;
+      # packages.x86_64-linux.hello = nixpkgs.legacyPackages.x86_64-linux.hello;
+      # defaultPackage.x86_64-linux = self.packages.x86_64-linux.hello;
+
+      devShell.x86_64-linux = with pkgs;
+        mkShell {
+          buildInputs = [
+            just
+            cargo
+            rustup
+          ];
+        };
+  };
+}