Added more docs

.github/workflows/nix-build.yml

@@ -0,0 +1,41 @@
+name: Nix Build and Cache
+
+on:
+  push:
+    branches: [main]
+    tags:
+      - 'v*'
+  pull_request:
+    branches: [main]
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: cachix/install-nix-action@v24
+        with:
+          extra_nix_config: |
+            experimental-features = nix-command flakes
+
+      - uses: cachix/cachix-action@v12
+        with:
+          name: gitea-mirror  # Your cache name
+          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+
+      - name: Build package
+        run: nix build --print-build-logs
+
+      - name: Check flake
+        run: nix flake check
+
+      - name: Test run (dry run)
+        run: |
+          # Just verify the binary exists and is executable
+          test -x ./result/bin/gitea-mirror
+          ./result/bin/gitea-mirror --version || echo "Version check skipped"