Added the background. Refactoring...
Added the background.
Refactoring...

domenicosolazzo/practice-swift,domenicosolazzo/practice-swift,hanhailong/practice-swift,hanhailong/practice-swift,nguyenantinhbk77/practice-swift,nguyenantinhbk77/practice-swift,hanhailong/practice-swift,hanhailong/practice-swift,domenicosolazzo/practice-swift,nguyenantinhbk77/practice-swift,domenicosolazzo/practice-swift,nguyenantinhbk77/practice-swift