add event_participants_path link
add event participants list view
add joined field to event_participants table
participant can check in event now
participants#index view used new layout now
sort by user.login as participant list
add test code
#229: writing preview
#229: change the tab name and remove unnecessary dependency
#229: change http method in order to fix markdown bug
#229: remove unnecessary lines
#229: add unit tests and functional test and improve codes
#229: refactor previewing functionality's js parts
used new search method because this wouldn't run sql in loop
add new test code
add spotlight icon to homepage.
merge.
reuse login_user.
when user is not the event creator, he can not allow to get check in event. #240
fixed rspec error.