Upgrade rails to version 4.2

[brauliobo]

Rails 4.2 has significant performance improvements

[brianhempel]

Upgrading Rails is an interesting proposal. I haven't done it yet because I view Is Ruby Fast Yet? as a Ruby benchmark...performance improvements should be because of interpreter improvements rather than Rails improvements.

I also realize that the current results are more relevant if they are running the latest version of Rails.

[brauliobo]

But you are using rails, and it is one of the slowest ruby frameworks, unfortunetely