Add basic README files

README.md

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+# Unipept Index
+
+![Codecov](https://img.shields.io/codecov/c/github/unipept/unipept-index?token=IZ75A2FY98&logo=Codecov)
+
+The unipept index written entirely in `Rust`. This repository consists of multiple different Rust projects that depend on 
+each other. More information about each project can be found in their respective `README.md` file.
+
+## Installation
+
+Clone this repository with the following command:
+
+```bash
+git clone https://github.com/unipept/unipept-index.git
+```
+
+And build the projects using:
+
+```bash
+cargo build --release
+```

fa-compression/README.md

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+# Functional Annotation Compression
+
+![GitHub Actions Workflow Status](https://img.shields.io/github/actions/workflow/status/unipept/unipept-index/test.yml?logo=github)
+![Codecov](https://img.shields.io/codecov/c/github/unipept/unipept-index?token=IZ75A2FY98&flag=fa-compression&logo=codecov)
+![Static Badge](https://img.shields.io/badge/doc-rustdoc-green)
+
+The `fa-compression` library offers compression for Unipept's functional annotation strings. These strings follow a very specific 
+format that the compression algorithm will use to achieve a guaranteed minimal compression of **50%** for both very large and very 
+small input strings. The compression ratio will often situate around **60-70%**.
+
+The compression algorithm never has to allocate extra memory to build an encoding table or something similar. We can encode each 
+string separately. This is particullary useful when all strings have to be encoded/decoded on their own. There is no need to decode 
+an entire database to only fetch a single entry.
+
+## Example
+
+```rust
+use fa_compression;
+
+fn main() {
+    let encoded: Vec<u8> = fa_compression::encode(
+        "IPR:IPR016364;EC:1.1.1.-;IPR:IPR032635;GO:0009279;IPR:IPR008816"
+    );
+
+    // [ 44, 44, 44, 189, 17, 26, 56, 173, 18, 116, 117, 225, 67, 116, 110, 17, 153, 39 ]
+    println!("{:?}", encoded);
+
+    let decoded: String = fa_compression::decode(&encoded);
+
+    // "EC:1.1.1.-;GO:0009279;IPR:IPR016364;IPR:IPR032635;IPR:IPR008816"
+    println!("{:?}", decoded);
+}
+```