add postmortem related talk from SREcon17Americas

README.md

@@ -45,4 +45,5 @@ In both cases the filename pattern is `postmortem-*`. For example, if you create
 * [Etsy’s Debriefing Facilitation Guide for Blameless Postmortems](https://codeascraft.com/2016/11/17/debriefing-facilitation-guide/)
 * [Writing Your First Postmortem](https://medium.com/production-ready/writing-your-first-postmortem-8053c678b90f)
 * [How to Write Great Outage Post-Mortems](https://artsy.github.io/blog/2014/11/19/how-to-write-great-outage-post-mortems/)
+* [Postmortem Action Items: Plan the Work and Work the Plan](https://www.usenix.org/conference/srecon17americas/program/presentation/lueder)
 * [Site Reliability Engineering resources](https://github.com/dastergon/awesome-sre)