add missed class property (issue #1758)
add missed class property (issue #1758)

juliangut/Slim,RealSelf/Slim,JoeBengalen/Slim,foxyantho/Slim,iinux/Slim,dopesong/Slim,Sam-Burns/Slim,iinux/Slim,slimphp/Slim,iinux/Slim,akrabat/Slim