update README (deps, adduser, ubuntu20.04)

README.md

@@ -29,20 +29,29 @@ Quick HOWTO
 Install
 -------
 
-Installation is only tested on Debian 10, even though it should work
-straightforward on any equivalent system.
+Installation has been tested on:
+
+* Debian 10 (buster)
+* Ubuntu 20.04 (Focal)
+
+However it should work straightforward on any equivalent system.
 
 ### Docker Install
 
     sudo apt install docker
+    sudo systemctl enable --now docker
 
-Check that your user is part of `docker` group:
+Check that your are member of `docker` group:
 
     sudo adduser <user> docker
 
 If needed, you need to logout and login again for the new group to
 become active.
 
+### Python Dependencies
+
+    sudo apt install python3-docker python3-dockerpty python3-xdg
+
 ### manual install
 
     cd <tools>