classes/Application.php
public function config($configurator)
	{
		if ($this->booted) {
			$this->invokeConfigurator($configurator);
		} else {
			$this->configurators->push($configurator);
		}
	}
public function config($configurator)
	{
		if ($this->booted) {
			$this->invokeConfigurator($configurator);
		} else {
			$this->configurators->push($configurator);
		}
	}
Push a configurator on top of the stack. The configurators will be
executed when the application is booted. If the application is already
booted, the configurator will be executed at once.

@param  callable|string|ConfiguratorInterface $configurator

@return void