add flake + default.nix

flake.nix

@@ -0,0 +1,18 @@
+{
+  description = "Kyle's Text Editor";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+  };
+
+  outputs =
+    { self, nixpkgs }:
+    let
+      pkgs = import nixpkgs { system = "x86_64-linux"; };
+    in
+    {
+      packages.x86_64-linux = {
+        default = pkgs.callPackage ./default.nix { };
+      };
+    };
+}