Add rust-bitcoin in Cryptocurrencies section

README.md

@@ -167,6 +167,7 @@ See also [Rust — Production](https://www.rust-lang.org/production) organizatio
 * [Parity-Zcash](https://github.com/paritytech/parity-zcash) — Rust implementation of the Zcash protocol
 * [Phala-Network/phala-blockchain](https://github.com/Phala-Network/phala-blockchain) — Confidential smart contract blockchain based on Intel SGX and Substrate
 * [Polkadot](https://github.com/paritytech/polkadot) — Heterogeneous multi‑chain technology with pooled security
+* [rust-bitcoin](https://github.com/rust-bitcoin/rust-bitcoin) — Library with support for de/serialization, parsing and executing on data structures and network messages related to Bitcoin.
 * [rust-cardano](https://github.com/input-output-hk/rust-cardano) — Rust implementation of Cardano primitives, helpers, and related applications
 * [Solana](https://github.com/solana-labs/solana) — Incredibly fast, highly scalable blockchain using Proof-of-History.
 * [Substrate](https://github.com/paritytech/substrate) — Generic modular blockchain template written in Rust