Add puma cookbook for 11.10 branch

[joe1chen]

This is an updated pull request to add Puma support but re-done against the 11.10 branch. The original pull request #116 is still open and seems to have been forgotten but it was done against the 11.4 branch.

There were a few minor differences between #116 and this pull request:

1. Changes to opsworks_ganglia cookbook
2. Changes to passenger_apache2 cookbook
3. Added dependencies to puma metadata.rb
4. Change minimum threads from 0 o 1.

[abuzzell]

Thanks for this. I am trying to test it, but I find that opsworks uses the default rails_stack.rb before it loads the custom one, so that having

"opsworks": { "rails_stack": { "name": "nginx_puma" } },

in the stack settings throws an error on deploy (unrecognized stack name), because the default rails_stack attribute doesn't recognize it.

I notice /var/lib/aws/opsworks/cache.stage1 contains the default, /var/lib/aws/opsworks/cache.stage2 contains mine.

Any idea why I might need to do to fix this?