List all users on the database

def list_users(app, appbuilder):
    """
        List all users on the database
    """
    _appbuilder = import_application(app, appbuilder)
    echo_header("List of users")
    for user in _appbuilder.sm.get_all_users():
        click.echo(
            "username:{0} | email:{1} | role:{2}".format(
                user.username, user.email, user.roles
            )
        )