code: def track!(args = nil)
        return unless @playground.collecting?
        timestamp, identity, values = track_args(args)
        connection.metric_track @id, timestamp, identity, values
        @playground.logger.info "vanity: #{@id} with value #{values.join(", ")}"
        call_hooks timestamp, identity, values
      end
docs: Takes playground (need this to access Redis), friendly name and optional
   id (can infer from name).
   -- Tracking --
   Called to track an action associated with this metric. Most common is not
   passing an argument, and it tracks a count of 1. You can pass a different
   value as the argument, or array of value (for multi-series metrics), or
   hash with the optional keys timestamp, identity and values.
  
   Example:
     hits.track!
     foo_and_bar.track! [5,11]