add link to releases

README.md

@@ -1,6 +1,9 @@
 ## Basic Bench Optics
+The repository contains the Mrsic-Flogel optics practical handout. 
+This is based on the [TENSS](http://www.tenss.ro/) basic [bench optics exercises](https://github.com/tenss/bench_optics). 
+You can find the latest PDF of the hand-out in the project's [Releases](https://github.com/BaselLaserMouse/bench_optics/releases).
 
-
-The repository contains the handout used for the TENSS basic bench exercises. The handout is written in Latex. 
-IMPORTANT: Please do not push PDFs of the built handout to the repository. Instead, build the PDF, create a release, 
-and add the PDF to the release. This avoids bloating the repo. 
+### Contributing
+The handout is written in Latex. 
+Please do not push PDFs of the built handout to the repository because it bloats the repository.
+Instead, you can upload PDFs to a release.