Puma scripts

In config/deploy.rb:

``` ruby
stage :staging do
  server "staging.sponsorpay.com", :web, :app
  set :repository, "git@github.com:spci/ofw.git"
  set :rails_env, 'staging'
  set :puma_worker_processes, 4
  set :puma_min_threads, 8
  set :puma_max_threads, 32
  after "deploy:symlink", "assets:build"
  set :copy_exclude, ".git/*"
end
```