Clarify slack link in readme

README.md

@@ -323,4 +323,5 @@ Furthermore, all tests in the ```tests``` directory will be run upon pushing cha
 
 # Contact
 If you are interested in machine learning models for LAM, have questions about the implementation or ideas for extending it, feel free to get in touch.
-You can join the [slack channel](https://join.slack.com/t/ml-lam/shared_invite/zt-2t112zvm8-Vt6aBvhX7nYa6Kbj_LkCBQ), open a github issue on this page, or (if more suitable) send an email to [[email protected]](mailto:[email protected]).
+There is an open [mllam slack channel](https://join.slack.com/t/ml-lam/shared_invite/zt-2t112zvm8-Vt6aBvhX7nYa6Kbj_LkCBQ) that anyone can join (after following the link you have to request to join, this is to avoid spam bots).
+You can also open a github issue on this page, or (if more suitable) send an email to [[email protected]](mailto:[email protected]).