Add link to readme pointing to monad example repo

Author: Simon Härer

README.md

@@ -132,6 +132,10 @@ functions that `clojure.core` does, but implemented via records and
 These can be very handy for using React-based libraries like [Reacl](https://github.com/active-group/reacl),
 which can optimize work based on the equality of values.
 
+### Monad
+
+An example usage of the `active.clojure.function` namespace can be found at https://github.com/active-group/active-clojure-monad-example
+
 ## License
 
 Copyright © 2014 Active Group GmbH