Rust learning project

Build and execute binaries with Nix

1. Get necessary dependencies with Nix: nix-shell -p cargo
2. Change into src directory: cd src
3. Build: cargo build
4. Execute binary: cargo run --bin <bin_name>

Part 1: The Rust Programming Language Book

1. Includes hello_cargo app that prints "Hello, World!"
2. Includes guessing_game app that lets you play a number guessing game until you win!