Puma starting in single mode...
2017-02-27T15:08:03.908788+00:00 app[web.1]: * Version 3.7.0 (ruby 2.3.1-p112), codename: Snowy Sagebrush
2017-02-27T15:08:03.908789+00:00 app[web.1]: * Min threads: 5, max threads: 5
2017-02-27T15:08:03.908790+00:00 app[web.1]: * Environment: production
2017-02-27T15:08:05.942041+00:00 app[web.1]: ! Unable to load application: NameError: uninitialized constant Api::V1::AController
2017-02-27T15:08:05.942133+00:00 app[web.1]: bundler: failed to load command: puma (/app/vendor/bundle/ruby/2.3.0/bin/puma)
2017-02-27T15:08:05.942266+00:00 app[web.1]: NameError: uninitialized constant Api::V1::AController

bundle exec puma -C config/puma.rb

workers Integer(ENV['WEB_CONCURRENCY'] || 2)
threads_count = Integer(ENV['RAILS_MAX_THREADS'] || 5)
threads threads_count, threads_count

preload_app!

rackup      DefaultRackup
port        ENV['PORT']     || 3000
environment ENV['RACK_ENV'] || 'development'

on_worker_boot do
    ActiveRecord::Base.establish_connection
end