# File lib/ruote/evt/tracker.rb, line 82
    def add_tracker (wfid, action, fei, conditions, msg, doc=nil)

      doc ||= @context.storage.get_trackers

      doc['trackers'][Ruote.to_storage_id(fei)] =
        { 'wfid' => wfid,
          'action' => action,
          'fei' => fei,
          'conditions' => conditions,
          'msg' => msg }

      r = @context.storage.put(doc)

      add_tracker(wfid, action, fei, msg, r) if r
        # the put failed, have to redo the work
    end