updatePosition(positionUpdate) {
    return new Promise((resolve, reject) => {
      this.db.run(
        `INSERT INTO users(workspaceId, lastEntryNumber, position)
          VALUES(?, -1, ?)
          ON CONFLICT(workspaceId)
          DO UPDATE SET position = ?`,
        [
          positionUpdate.workspaceId,
          JSON.stringify(positionUpdate.position),
          JSON.stringify(positionUpdate.position),
        ],
        (err) => {
          if (err) {
            console.error(err.message);
            reject();
          }
          resolve();
        },
      );
    });
  }
Update the position in the users table for a given user.
@param {!Object} positionUpdate The positionUpdate with the new
position for a given user.
@returns {!Promise} Promise object represents the success of the update.
@public