实现的小功能：判断报名是否重复，是返回true,否返回false.

Message.judge_sign_up_repeat = function (sms_json) {
var sign_ups = JSON.parse(localStorage.sign_ups);
var activity = _.filter(sign_ups, function (num) {
return num.activity_id == Activity.get_current_activity()
})
return  _.some(activity, function (list) {
return list.phone == Message.save_phone(sms_json)
})
}

Message.judge_sign_up_repeat = function (sms_json) {
var sign_ups = JSON.parse(localStorage.sign_ups);
var activity = _.find(sign_ups, function (num) {
return num.activity_id == Activity.get_current_activity()
})
var sign_up_reepeat= _.some(activity, function (value,key) {
return key=='phone' ? value == Message.save_phone(sms_json) : ''
})
return sign_up_repeat
}

Message.judge_sign_up_repeat = function (sms_json) {
var sign_ups = JSON.parse(localStorage.sign_ups);
var activity = _.find(sign_ups, function (num) {
return num.activity_id == Activity.get_current_activity()
})
var sign_up_repeat = activity ? activity['phone']== Message.save_phone(sms_json) : false
}
return sign_up_repeat
}