text: var sqlite3 = require('sqlite3');
  var db = new sqlite3.Database('storage.db');
  
  module.exports.list = (callback) => {
    db.all("SELECT gid, displayName FROM groups", (err, rows) => {
      if (err) {
        callback(err, null);
        return;
      }
      if (!rows.length) {
        err = new Error('No groups');
        callback(err, null);
        return;
      }
      callback(null, rows);
    });
  };