add memory and dual core recommendations

Author: coding-horror

docs/INSTALL-ubuntu.md

@@ -1,5 +1,12 @@
 # Discourse Install Guide on Ubuntu
 
+## What kind of hardware do you have?
+
+- We *strongly* recommend 2GB of memory minimum if you don't want to deal with swap partitions during the install.
+- We recommend at least a dual core CPU.
+
+You can get away with less than this if you are careful -- 1 GB of memory and a single core CPU are the minimums -- but it's simpler to just throw a bit more hardware at the problem.
+
 ## Install Ubuntu Server 12.04 LTS with the package groups:
 
 ![screenshot of package group selection screen](https://raw.github.com/discourse/discourse-docimages/master/install/ubuntu%20-%20install%20-%20software%20selection.png)