Add 'The Art of Capacity Planning'

@@ -54,6 +54,7 @@
 * [Agile Retrospectives: Making Good Teams Great](http://www.amazon.com/Agile-Retrospectives-Making-Teams-Great/dp/0977616649) (Derby et al.)
 * [Better: A Surgeon’s Notes on Performance](http://www.amazon.com/dp/0312427654) (Gawande)
 * [The Checklist Manifesto: How to Get Things Right](http://www.amazon.com/The-Checklist-Manifesto-ebook/dp/B0030V0PEW) (Gawande)
+* [The Art of Capacity Planning: Scaling Web Resources](http://www.amazon.com/The-Art-Capacity-Planning-Resources/dp/0596518579) (Allspaw)
 
 #### Research Groups