fix typo and indention in spec file
show list of participants avatars
add helper method to return recent participated users
show only 10 recent participated users
link participant avatar to user profile page
show user profile as popover when hover on participant avartar
Prepand hr before participants in event page
Merge branch 'feature/223-participants-list' of git://github.com/doitian/19wu into doitian-feature/223-participants-list
change hr style.

add participants label.