```ruby
# https://devcenter.heroku.com/articles/rails-unicorn
require 'redis'

worker_processes 3
timeout 15
preload_app true

before_fork do |server, worker|
  defined?(ActiveRecord::Base) && ActiveRecord::Base.connection.disconnect!
end

after_fork do |server, worker|
  defined?(ActiveRecord::Base) && ActiveRecord::Base.establish_connection
  defined?(Redis) && Redis.current.disconnect!
end
```

Update Unicorn's config for production.
user
```ruby
require 'redis'

app_path = File.expand_path(File.dirname(__FILE__) + '/..')
working_directory = app_path

worker_processes (ENV["UNICORN_WORKERS"] || 3).to_i

listen (ENV["UNICORN_PORT"] || 3000).to_i

if ENV["RAILS_ENV"] == "production"
  stderr_path "#{app_path}/log/unicorn.stderr.log"
  stdout_path "#{app_path}/log/unicorn.stdout.log"
  pid "#{app_path}/tmp/pids/unicorn.pid"
end

timeout 30

preload_app true

before_fork do |server, worker|
  defined?(ActiveRecord::Base) && ActiveRecord::Base.connection.disconnect!
end

after_fork do |server, worker|
  defined?(ActiveRecord::Base) && ActiveRecord::Base.establish_connection
  defined?(Redis) && Redis.current.disconnect!
end
```
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