query(serverId) {
    return new Promise((resolve, reject) => {
      this.db.all(
        `SELECT * from eventsdb WHERE serverId > ${serverId};`,
        (err, entries) => {
          if (err) {
            console.error(err.message);
            reject('Failed to query the database.');
          } else {
            entries.forEach((entry) => {
              entry.events = JSON.parse(entry.events);
            });
            resolve(entries);
          }
        },
      );
    });
  }
Query the database for entries since the given server id.
@param {number} serverId serverId for the lower bound of the query.
@returns {!Promise} Promise object represents the entries since the last
given serverId.
@public