Solution: Found this in puma/capistrano.rb
def config_file
@_config_file ||= begin
file = fetch(:puma_config_file, nil)
file = "./config/puma/#{puma_env}.rb" if !file && File.exists?("./config/puma/#{puma_env}.rb")
file
end
end
Just add the options in this file, if it's production, otherwise change the file name to appropriate environment.
/config/puma/production.rb