Tailing a MongoDB capped collection.rb

#Kind of like tail -f -n1
db   = Mongo::Connection.new(mongo_hostname).db(mongo_dbname)
coll = db.collection(mongo_collection)
start_count = coll.count
tail = Mongo::Cursor.new(coll, :tailable => true, :order => [['$natural', 1]]).skip(start_count- 1)
loop do
  if doc = tail.next_document
    puts doc
  else
    sleep 1
  end
end