task#5419 fix css poll & button link
Merge pull request #56 from tunghdt91/task#5419

task#5419 fix css poll & button link
task#5418 add poll result view
Merge pull request #57 from thaipt1012/task#5418

task#5418 add poll result view
fix unable to delete poll
Merge pull request #55 from cuongnv540/task#5420

fix unable to delete poll
Task #5423 Change poll index view