Add attic

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

scripts/cache.sh

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+flake_json=$(nix flake show --json)
+
+build_and_push() {
+  local expr="$1"
+  nix build "$expr" --no-link --print-out-paths | while IFS= read -r path; do
+    attic push main "$path"
+  done
+}
+
+jq -r '.nixosConfigurations | keys[]' <<<"$flake_json" | while IFS= read -r cfg; do
+  expr=".#nixosConfigurations.\"$cfg\".config.system.build.toplevel"
+  build_and_push "$expr"
+done