presentations: add talk about Flatpak by Simon McVittie

Signed-off-by: Dylan Aïssi <dylan.aissi@collabora.com>

content/overview/presentations.md

@@ -104,7 +104,12 @@ Apertis community have previously shared (ordered newest to oldest):
 * [Application Framework APIs in action - a case study](/images/genivi-amm-2017-slides.odp)
   - Introduction to application framework for GENIVI and Apertis by Ekaterina
     Gerasimova and Andre Magalhães
-  - Presented at the *GENIVI All Member Meeting 2017*
+  - Presented at the *GENIVI All Member Meeting 2017*  
+ 
+* [A Debian maintainer's guide to Flatpak](https://www.youtube.com/watch?v=9SmZYQAqBd8)
+  - An overview of how Flatpak and its portals behave and how they’re implemented by
+    Simon McVittie
+  - Presented at the [DebConf17](https://debconf17.debconf.org/)
 
 # 2016