code: function addFilter (config, filter) {
    if (filter) {
      if (filter[ 0 ] === '-') {
        config.filters.ignore[ filter ] = new RegExp('^' + filter.slice(1).replace(/[*]/g, '.*?') + '$')
      } else {
        config.filters.should[ filter ] = new RegExp('^' + filter.replace(/[*]/g, '.*?') + '$')
      }
    }
  }
docs: add the regex filter to the right hash for use later