add formatter to flake

.forgejo/workflows/tests.yml

@@ -6,6 +6,21 @@ on:
   workflow_dispatch:
 
 jobs:
+  nix:
+    runs-on: docker
+    container:
+      image: nix
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Nix doctor
+        run: nix doctor
+      - name: Check flake
+        run: nix flake check --all-systems
+      - name: Build flake
+        run: nix build --print-out-paths
+      - name: Flake info
+        run: nix flake info
   tests:
     runs-on: docker
     container:

flake.nix

@@ -21,8 +21,10 @@
         src = ./.;
         modules = ./gomod2nix.toml;
       };
-    in {
-      defaultPackage = sanic;
+    in
+    {
+      packages.default = sanic;
+      formatter = pkgs.nixpkgs-fmt;
       devShells.default = pkgs.mkShell {
         buildInputs = with pkgs; [
           go