Add timestamps for video 17 Ravin Welcome

### Reference
Towards pymc-devs#11
Closes pymc-devs#19

### Description
Add timestamps for video 17 Ravin Welcome

videos-list/17-ravin.md

@@ -13,12 +13,17 @@ Discourse Discussion
 https://discourse.pymc.io/t/welcome-to-pymcon/5928
 
 ## Timestamps
-- 0:00 Start of event
-- x:xx 
-- x:xx
-
-## Note: help us add timestamps here
-https://github.com/pymc-devs/video-timestamps
+00:00 Welcome by Ravin
+00:47 About Ravin
+01:25 PyMCon 2020 - an asynchronous-first virtual conference for the Bayesian community
+01:47 Building a community
+02:27 The volunteers
+02:59 The sponsors
+03:42 Code of conduct
+04:05 The speakers
+04:47 The asynchronous events
+06:26 The synchronous events
+08:01 Registration
 
 Speaker bio:
 Ravin is a data scientist at Google where he uses data to inform decisions. He has previously worked at Sweetgreen, designing systems that would benefit team members and communities through sustainable and healthy food, and SpaceX, creating tools that would ultimately launch rocket ships.