📝 docs: add a link to the new development guide page (#340)

docs/README.md

@@ -15,5 +15,6 @@
 
 # Developers
 
+- [Developing](./developing.md)
 - [**Contribute**](https://github.com/neon-mmd/websurfx/blob/master/CONTRIBUTING.md)
 - [**Coding style**](https://rust-lang.github.io/api-guidelines/naming.html)