Move Nix files back to the root of the project

pkgs/notes/default.nix

@@ -0,0 +1,27 @@
+{ pkgs, ... }:
+
+with pkgs;
+
+stdenv.mkDerivation rec {
+  pname = "notes";
+  version = "0.3.0";
+
+  src = fetchFromGitHub {
+    owner = "nickjj";
+    repo = "notes";
+    rev = "v${version}";
+    sha256 = "gyrsTWPT8w4DsRim3jlbjvpXwX/y+7SwLaM+3LVOJdU=";
+  };
+
+  buildInputs = [ bash ];
+
+  patches = [
+    ./create-daily-notes.patch
+  ];
+
+  installPhase = ''
+    mkdir -p $out/bin
+    cp notes $out/bin/notes
+    chmod +x $out/bin/notes
+  '';
+}