Add link to slides for "Ossum with Gerrit" talk

Change-Id: I0be1ac5d9e938669eda4f7b3bff5a5ca491684fd

lightning-talks/ossum-with-gerrit.md

diff --git a/lightning-talks/ossum-with-gerrit.md b/lightning-talks/ossum-with-gerrit.md
index 6818e0a..c24beef 100644
--- a/lightning-talks/ossum-with-gerrit.md
+++ b/lightning-talks/ossum-with-gerrit.md
@@ -12,4 +12,6 @@
 In addition to a brief introduction to ossum, this lightning talk will cover why we
 chose Gerrit (again!) and what are some lessons learnt from TeamForge.
 
+[Slides](https://storage.cloud.google.com/gerrit-talks/summit/2019/ossum-GUS_2019.pdf)
+
 *[Miikka Andersson -- CollabNet](../speakers.md#mandersson)*