added nix action

.github/workflows/docker.yml

@@ -13,11 +13,11 @@ env:
 
 jobs:
     build:
-
         runs-on: ubuntu-latest
 
         steps:
             - uses: actions/checkout@v4
+            - uses: hustcer/setup-nu@v3
             - uses: cachix/install-nix-action@v31
               with:
                   nix_path: nixpkgs=channel:nixos-unstable