Add 'Architecture of a Database System' and 2015-05-20 schedule

@@ -34,6 +34,7 @@ We welcome [suggestions](CONTRIBUTING.md).
 * [Resident Distributed Datasets: a Fault-Tolerant Abstraction for In-Memory Cluster Computing](https://www.usenix.org/system/files/conference/nsdi12/nsdi12-final138.pdf) (Zahari et al.)
 * [The Human Side of Postmortems](https://docs.google.com/file/d/0Byl4UKRYLErDVlJMNDNjaThiR2M/edit) (Zwieback)
 * [Crew Resource Management: a Positive Change for the Fire Service](http://www.iaff.org/06news/NearMissKit/6.%20Crew%20Resource%20Management/CRM.pdf)
+* [Architecture of a Database System](http://db.cs.berkeley.edu/papers/fntdb07-architecture.pdf) (Hellerstein et al.)
 
 
 #### Posts

@@ -1,5 +1,8 @@
 # Schedule for 8th Light reading group
 
+## 2015-05-20
+* Sections 1-3 of [Architecture of a Database System](http://db.cs.berkeley.edu/papers/fntdb07-architecture.pdf) (Hellerstein et al.)
+
 ## 2015-05-13
 * [The Unified Logging Infrastructure for Data Analytics at Twitter](http://vldb.org/pvldb/vol5/p1771_georgelee_vldb2012.pdf) (Lee et al.)