add to_ng_init method to Hash class.
add check in and join helper.
add event check in helper test.
add event join helper test.
add user joined? and checked_in? method.
add user joined? and checked_in? rspec test.
combine event join and check in action.
add user joined? and checked_in javascript test.
fixed: started event should not be join.
fixed rspec error when event end_time is nil.
make sure check in panel to be show after user join.
use value.inspect instead of "'#{value}'"
fixed rspec error.
Merge pull request #443 from saberma/saberma-bug/402-checked-in-button-should-not-be-click

活动页面已签到按钮不能点击 #402