class Sinatra::Base

def run!(options = {}, &block)

with the constructed handler once we have taken the stage.
Thin, Puma, Mongrel, or WEBrick (in that order). If given a block, will call
Run the Sinatra app as a self-hosted server using 
def run!(options = {}, &block)
  return if running?
  set options
  handler         = detect_rack_handler
  handler_name    = handler.name.gsub(/.*::/, '')
  server_settings = settings.respond_to?(:server_settings) ? settings.server_settings : {}
  server_settings.merge!(:Port => port, :Host => bind)
  begin
    start_server(handler, server_settings, handler_name, &block)
  rescue Errno::EADDRINUSE
    $stderr.puts "== Someone is already performing on port #{port}!"
    raise
  ensure
    quit!
  end
end