Delete flake shell

shells/flake.nix

@@ -1,18 +0,0 @@
-{
-  description = "Immutable NixOS development shells.";
-
-  inputs = {
-    flake-utils.url = "github:numtide/flake-utils";
-  };
-
-  outputs = inputs @ { self, nixpkgs, ... }:
-    inputs.flake-utils.lib.eachDefaultSystem (system:
-      let pkgs = nixpkgs.legacyPackages.${system};
-      in
-        rec {
-          devShells.default = pkgs.mkShell {
-            
-          };
-        }
-    );
-}