Fix a warning by adding missed serialVersionUID.
Fix a warning by adding missed serialVersionUID.

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