add rustr to FFI section
@ -138,6 +138,8 @@ See also [Foreign Function Interface](https://doc.rust-lang.org/book/ffi.html),
* Python
* [dgrunwald/rust-cpython](https://github.com/dgrunwald/rust-cpython) — Python bindings [<img src="https://travis-ci.org/dgrunwald/rust-cpython.svg?branch=master">](https://travis-ci.org/dgrunwald/rust-cpython)
* [lukemetz/rustpy](https://github.com/lukemetz/rustpy) — Python bindings [<img src="https://travis-ci.org/lukemetz/rustpy.svg?branch=master">](https://travis-ci.org/lukemetz/rustpy)
* R
* [rustr/rustr](https://github.com/rustr/rustr) — use Rust from R, and use R in Rust [<img src="https://travis-ci.org/rustr/rustr.svg?branch=master">](https://travis-ci.org/rustr/rustr)
### IDEs