task#5346 user invite people in private poll
Merge pull request #69 from tunghdt91/task#5346

task#5346 user invite people in private poll
task#5417 create logic for poll display settings : public, private, restricted
Merge pull request #70 from caoluc/task#5417

task#5417 create logic for poll display settings : public, private, rest...
Bug #5480 fix admin delete poll/choice