add devenv to github workflows

.github/workflows/devenv.yml

@@ -0,0 +1,28 @@
+name: "devenv build"
+
+on:
+  pull_request:
+  push:
+
+jobs:
+  tests:
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+    runs-on: ${{ matrix.os }}
+
+    steps:
+    - uses: actions/checkout@v4
+    - uses: cachix/install-nix-action@v26
+    - uses: cachix/cachix-action@v14
+      with:
+        name: devenv
+
+    - name: Install devenv.sh
+      run: nix profile install nixpkgs#devenv
+
+    - Name: Check formatting
+      run: devenv shell check-fmt
+
+    - name: Build the project
+      run: devenv shell build

devenv.nix

@@ -8,7 +8,15 @@
 
   languages.rust.enable = true;
 
-  scripts.build.exec = ''bacon'';
+  # Build the project
+  scripts.build.exec = ''
+    cargo build --release
+  '';
+
+  # Check the formatting of the project
+  scripts.check-fmt.exec = ''
+    cargo fmt --all -- --check
+  '';
 
   enterTest = ''
     echo "Running tests"