Add Substrate (#1869)

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

readme.md

@@ -573,6 +573,7 @@
 - [EOSIO](https://github.com/DanailMinchev/awesome-eosio#readme) - A decentralized operating system supporting industrial-scale apps.
 - [Corda](https://github.com/chainstack/awesome-corda#readme) - Open source blockchain platform designed for business.
 - [Waves](https://github.com/msmolyakov/awesome-waves#readme) - Open source blockchain platform and development toolset for Web 3.0 apps and decentralized solutions.
+- [Substrate](https://github.com/substrate-developer-hub/awesome-substrate#readme) - Framework for writing scalable, upgradeable blockchains in Rust.
 
 ## Higher Education