async function getByRole(role) {
  const queryParams = {
    attributes: ['id', 'firstname', 'lastname', 'selector', 'email', 'language'],
    offset: 0,
    order: [['firstname', 'ASC']],
    where: {
      role,
    },
  };

  const users = await db.User.findAll(queryParams);

  const usersPlain = users.map((user) => {
    // we converted the user to plain object
    return user.get({ plain: true });
  });

  return usersPlain;
}
@private
@description Get list of users by role.
@name gladys.user.getByRole
@param {string} role - The role of the users.
@returns {Promise} Promise.
@example
await gladys.user.getByRole('admin');