Update README with links

Author: wolfv

2018-09-20-berlin-cplusplus-meetup/README.md

@@ -6,4 +6,20 @@ The slides of the C++ Meetup in Berlin (September 18th, 2018)
 can be found in this folder.
 
 The presentation is located inside the Berlin-cplusplus-2018.ipynb notebook.
-The other example notebooks as indicated.
+
+## Interactive Demos Here:
+
+To access the interactive demos *ONLINE* and *WITHOUT* installation, click the "Binder" Button on each of these. 
+
+Like this → [![Binder](https://img.shields.io/badge/launch-binder-brightgreen.svg)](https://mybinder.org/v2/gh/QuantStack/xtensor/stable?filepath=notebooks/xtensor.ipynb)
+
+- https://github.com/QuantStack/xeus-cling
+- https://github.com/QuantStack/xtensor
+- https://github.com/QuantStack/xwidgets
+- https://github.com/QuantStack/xleaflet
+- https://github.com/QuantStack/xplot
+- https://github.com/QuantStack/xvolume
+
+## Join the community on gitter
+
+https://gitter.im/QuantStack/Lobby