removed Cargo.lock and shell.nix from .gitignore

.gitignore

@@ -1,9 +1,8 @@
 /target
 /.idea
 /src/debug_emails.txt
-Cargo.lock
 *.sqlite
 *.sqlite3
 .direnv
-shell.nix
 pandoc*.txt
+.envrc

shell.nix

@@ -0,0 +1,25 @@
+{pkgs ? import <nixpkgs> {}}: let
+  rust-toolchain = pkgs.symlinkJoin {
+    name = "rust-toolchain";
+    paths = with pkgs; [rustc cargo rustPlatform.rustcSrc rustfmt clippy];
+  };
+in
+  pkgs.mkShell {
+    nativeBuildInputs = with pkgs.buildPackages; [
+      rust-toolchain
+
+      pkg-config
+      xe
+      xz
+
+      cargo-tarpaulin
+      openssl
+      sqlite
+      gcc
+      gnumake
+
+      # dotnet-sdk_8
+    ];
+
+    RUST_SRC_PATH = "${pkgs.rust.packages.stable.rustPlatform.rustLibSrc}";
+  }