I think you can use the new signaling feature, monitor the memory metric and start the instance using api.
I have not done it with Rails, but with java in Tomcat. We used tomcat valves/scripts to detect the memory usage and post it in Amazon cloudWatch as Custom cloud watch metrics. You can create an scale out trigger based on cloudwatch alarm monitoring this metric.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.