sops: Improve secrets provisioning to split out staging

flake.nix

@@ -84,6 +84,9 @@
             # can easily test locally with the VM.
             services.nginx.domain = lib.mkOverride 99 "localhost";
 
+            # Use the staging secrets
+            sops.defaultSopsFile = lib.mkOverride 99 ./keys/staging.yaml;
+
             # # Set up VM settings to match real VPS
             # virtualisation.memorySize = 3941;
             # virtualisation.cores = 2;