test-vm: Add WHIB backend

flake.nix

@@ -37,6 +37,11 @@
       url = "git+ssh://gitea@git.ppp.pm:1122/alex/ppp.pm-site.git?ref=main";
       inputs.nixpkgs.follows = "nixpkgs";
     };
+
+    whib-backend = {
+      url = "git+ssh://gitea@git.ppp.pm:1122/alex/whib.git?ref=master";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
   };
 
   outputs =
@@ -77,13 +82,20 @@
           ];
         };
 
-        test-vm = inputs.nixpkgs.lib.nixosSystem {
-          system = "x86_64-linux";
-          specialArgs = {
-            inherit inputs;
+        test-vm =
+          let
+            system = "x86_64-linux";
+          in
+          inputs.nixpkgs.lib.nixosSystem {
+            inherit system;
+            specialArgs = {
+              inherit inputs;
+            };
+            modules = [
+              ./hosts/test-vm/configuration.nix
+              inputs.whib-backend.nixosModules.${system}.default
+            ];
           };
-          modules = [ ./hosts/test-vm/configuration.nix ];
-        };
       };
 
       devShells =