Change crate name to 'haggis' and add a README

Cargo.toml

@@ -1,5 +1,5 @@
 [package]
-name = "tar-ng"
+name = "haggis"
 version = "0.1.0"
 edition = "2021"
 

Format.md

@@ -0,0 +1 @@
+# TODO

README.md

@@ -0,0 +1,32 @@
+A modern archive format for serializing files, like Tar or Zip
+Contents
+========
+- [Features](#features)
+- [Building](#building)
+- [Contributing](#contributing)
+
+## Features
+For a more full specification of the format, please see [Format.md](Format.md)
+- No padding between metadata fields or data segments so it only stores the data
+  required to recreate the original file
+- Optional inline checksumming using a choice of md5, sha1 or sha256 algorithms
+  to ensure data integrity
+- Easily parallelized library code
+- Uses generic `Read` and `Write` interfaces from Rust `std` to support reading
+  archive nodes from anything that can supply a stream of data
+
+## Building
+The minimum supported Rust version (MSRV) for this project is currently Rust 1.65.
+The crate can be added to your project by adding it to your `Cargo.toml` file.
+Until the api is more mature you will have to use the crate from it's git repository
+rather than from the crates.io package registry.
+```Toml
+[dependencies.haggis]
+git = "https://codeberg.org/jeang3nie/haggis.git"
+```
+## Contributing
+Contributions are always welcome. Please run `cargo fmt` and `cargo clippy` and
+fix any issues before sending pull requests on Codeberg or patches via `git send-email`.
+
+In addition to contributing to the Rust implementation here, it would be welcome
+to see Haggis implemented in other languages.