add nixos CI

.drone.yml

@@ -6,3 +6,7 @@ steps:
     image: registry.gitlab.com/pipeline-components/yamllint
     commands:
       - yamllint -c .yamllint.yaml .
+  - name: nix flake check
+    image: nixos/nix:master
+    commands:
+      - nix --extra-experimental-features nix-command --extra-experimental-features flakes flake check --no-build

flake.nix

@@ -86,7 +86,9 @@
       nixosConfigurations = lib.foldr (el: acc: acc // mkConfig el) { } nixHosts;
       deploy.nodes = lib.foldr (el: acc: acc // mkDeploy el) { } nixHosts;
 
-      apps.${system} = {
+
+      apps.${system} = rec {
+        default = deploy;
         deploy = {
           type = "app";
           program = "${deploy-rs.packages.${system}.deploy-rs}/bin/deploy";