How to install Hrtor HEAD

Hrtor HEAD can be used by:

1. with Nix package manager
2. with Rust-lang's Cargo

Just use Nix package manager such as:

nix run github:haruki7049/hrtor#hrtor
# OR
nix run github:haruki7049/hrtor#hrtor -- your_file.txt

Or run with Cargo as:

cargo install --git https://github.com/haruki7049/hrtor