This crate provides utilities for implementing inverted indexes
```rust
let mut document_list: Vec
inverted_index_util::document_list::insert_document_mut(&mut document_list, b"aaaaaaaaaaaaaaaa");
inverted_index_util::document_list::insert_document_mut(&mut document_list, b"cccccccccccccccc");
inverted_index_util::document_list::insert_document_mut(&mut document_list, b"aaaaaaaaaaaaaaaa");
inverted_index_util::document_list::insert_document_mut(&mut document_list, b"bbbbbbbbbbbbbbbb");
assert_eq!(&document_list[..], &b"aaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbcccccccccccccccc"[..]);
```