Add note about stand-alone version in readme

README.md

@@ -14,6 +14,9 @@ Primarily, Aug\[m\]entile is intended to be added as a
 [widget](https://matrix.org/blog/2017/08/23/introducing-matrix-widgets),
 and the game subsequently be played inside a Matrix client with
 widget support, e.g. the [Element](https://element.io/) web client.
+It can also be run stand-alone, taking the place of a Matrix client
+in that case.
+[Join your favourite room here](https://augmentile.auglement.team)!
 
 ### Use cases