IssueApp: move excel download code into issues method
IssueApp: move excel download code into issues method

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