add tree_hugger and models-dev flake inputs

flake.nix

@@ -60,6 +60,14 @@
       url = "github:peteonrails/voxtype";
       inputs.nixpkgs.follows = "nixpkgs-unstable";
     };
+    tree_hugger = {
+      url = "git+ssh://git@github.com/everii-Group/tree_hugger";
+      inputs.nixpkgs.follows = "nixpkgs-unstable";
+    };
+    models-dev = {
+      url = "github:anomalyco/models.dev";
+      flake = false;
+    };
   };
   outputs =
     {