Add Justus Sagemüller (myself) to the CONTRIBUTORS file.

CONTRIBUTORS.md

@@ -16,6 +16,7 @@ We are grateful for contributions and would like to acknowledge all people who h
 * [Kati Niinimäki](https://github.com/niinimaki). Implemented the `WaveletTransform`.
 * [Willem Jan Palenstijn](https://github.com/wjp). Added adjoint of `RayTransform`.
 * [Axel Ringh](https://github.com/aringh). Created much of the `odl.solvers` module, in particular oversaw the addition of `Functional`.
+* [Justus Sagemüller](https://github.com/leftaroundabout). Package maintainer since 2024. Compatibility fixes and ongoing work on PyTorch backend.
 * [Olivier Verdier](https://github.com/olivierverdier). Typos.
 * [Gustav Zickert](https://github.com/zickert). Started the `odl.contrib.fom` package.
 * [Ozan Öktem](https://github.com/ozanoktem). Father of the project. Proposed the idea and made sure we had money to get it done!