docs: Link to the rust firmware project

docs/badge/firmware-development.rst

@@ -189,6 +189,11 @@ Then, you can run your firmware by distributing the resulting ``.bin`` file and
 
 For an example, see our doom port at **TODO**.
 
+Rewrite it in Rust
+^^^^^^^^^^^^^^^^^^
+
+If you fancy playing with Rust on the flow3r, check out the `flow3-rs <https://git.flow3r.garden/flow3r/flow3-rs>`_ project.
+
 Hardware Generations
 --------------------