add a flake file for development environment

flake.nix

@@ -0,0 +1,35 @@
+{
+  description = "Rust development environment with Cargo dependencies";
+
+  # Specify the inputs, such as nixpkgs
+  inputs = {
+    nixpkgs.url = "nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  # Define the outputs
+  outputs = { self, nixpkgs, flake-utils }: flake-utils.lib.eachDefaultSystem (system: let
+    pkgs = import nixpkgs { inherit system; };
+  in {
+    # Define a devShell for development
+    devShell = pkgs.mkShell {
+      # Add Rust and Cargo to the environment
+      buildInputs = [
+        pkgs.rustup
+      ];
+
+      # Optionally, set environment variables
+      CARGO_HOME = "./.cargo";
+      RUST_BACKTRACE = "1"; # Enable backtrace for debugging
+
+      # Optional shellHook to fetch dependencies when entering the shell
+      shellHook = ''
+        echo "Entering Rust development environment..."
+        rustup default nightly
+        cargo install rerun-cli
+        cargo fetch # Pre-fetch dependencies defined in Cargo.toml
+      '';
+    };
+  });
+}
+