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
used new search method because this wouldn't run sql in loop
add new test code
merge.
reuse login_user.
when user is not the event creator, he can not allow to get check in event. #240
fixed rspec error.
show check in link. #240
Merge branch 'master' of github.com:saberma/19wu
#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