Update Readme

README.md

@@ -25,6 +25,10 @@ The above paper contains theoretical results and several applications that can b
 
 This python toolbox is currently under development and is hosted on Gitlab. If you encounter a bug or something unexpected please let me know by [raising an issue](https://gitlab-research.centralesupelec.fr/2020elvirac/slope-screening/-/issues) on the project page or by contacting me by mail.
 
+## !Important Remark!
+
+This repository has been migrated to GitHub, please find the latest version at [slopescreening](https://github.com/c-elvira/slopescreening).
+
 ## Requirements
 
 This toolbox works with python 3.5+.