Replaces unicorn by puma
Adds logging for FetchFeeds tasks
Adds capo for deployment
Adds airbrake
Adds newrelic
Adds puma capo recipe
Set puma_cmd in capistrano to use the config and start one thread with one worker.

The thread/worker config is a workaround for newrelic:
https://github.com/puma/puma/issues/128