State::addStepChain

public function addStepChain($step)
{
	$chain = $this[self::CHAIN_NAME_VAR];
	$lastStep = end($chain);

	if($lastStep != $step)
	{
		$chain[] = $step;
		$this[self::CHAIN_NAME_VAR] = $chain;
	}

	return $this;
}