remove unused commnets & add some comments
remove unused commnets & add some comments

yona-projects/yona,oolso/yobi,bloodybear/yona,ChangsungKim/TestRepository01,doortts/fork-yobi,ihoneymon/yobi,ihoneymon/yobi,doortts/fork-yobi,yona-projects/yona,brainagenet/yobi,Limseunghwan/oss,ihoneymon/yobi,yona-projects/yona,oolso/yobi,brainagenet/yobi,violetag/demo,bloodybear/yona,oolso/yobi,ahb0327/yobi,brainagenet/yobi,bloodybear/yona,doortts/fork-yobi,bloodybear/yona,violetag/demo,doortts/forked-for-history,ahb0327/yobi,doortts/forked-for-history,yona-projects/yona,ahb0327/yobi,naver/yobi,naver/yobi,doortts/fork-yobi,naver/yobi,Limseunghwan/oss,doortts/forked-for-history,Limseunghwan/oss,ChangsungKim/TestRepository01