json.id discuss.id
json.content content_safe(discuss.content)
json.time time_from_now(discuss.created_at)
json.hack_id discuss.dis_id
# 主贴和回复有一些不同点
if discuss.parent_id
  json.can_delete discuss.can_deleted?(current_user)
else
  json.praise_count discuss.praises_count
  json.user_praise discuss.praise_treads.select{|pt| pt.user_id == current_user.id}.length > 0
end