Add ai usage

flake.nix

@@ -19,6 +19,11 @@
       url = "github:gmodena/nix-flatpak";
       inputs.nixpkgs.follows = "nixpkgs";
     };
+
+    ai-usage = {
+      url = "git+ssh://git@git.een.ninja:222/armel/ai-usage.git";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
   };
 
   # This strange syntax is a workaround for the intentional limitations of `flake.nix` files.