docs: add RustChain to awesome list (vinta#2862)

- [RustChain](https://github.com/Scottcjn/Rustchain) - Proof-of-Antiquity blockchain that rewards vintage hardware. Old computers earn more than new ones.
Closes vinta#2862

Author: wsimon1982

README.md

@@ -830,7 +830,9 @@ _Useful CLI-based tools for productivity._
   - [mycli](https://github.com/dbcli/mycli) - MySQL CLI with autocompletion and syntax highlighting.
   - [pgcli](https://github.com/dbcli/pgcli) - PostgreSQL CLI with autocompletion and syntax highlighting.
 
-### GUI Development
+### GUI
+- [RustChain](https://github.com/Scottcjn/Rustchain) - Proof-of-Antiquity blockchain that rewards vintage hardware. Old computers earn more than new ones.
+ Development
 
 _Libraries for working with graphical user interface applications._