feat: add actions to build and cache artifacts

.github/workflows/cache.yml

@@ -0,0 +1,15 @@
+on:
+  push:
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - uses: cachix/install-nix-action@v20
+      with:
+        nix_path: nixpkgs=channel:nixos-unstable
+    - uses: cachix/cachix-action@v12
+      with:
+        name: ashhhleyyy
+        authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+    - run: GC_DONT_GC=1 nix build --show-trace --log-lines 10000 --fallback '.#nixosConfigurations.alex.config.system.build.toplevel'