Login: fixed to go to the index page
Login: fixed to go to the index page

* When a logined user visits login page, then move to the index page.
* Whan a logined user visits signup page, then move to the index page.

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