async function sendDockerHostList(socket) {
    const timeLogger = new TimeLogger();

    let result = [];
    let list = await R.find("docker_host", " user_id = ? ", [
        socket.userID,
    ]);

    for (let bean of list) {
        result.push(bean.toJSON());
    }

    io.to(socket.userID).emit("dockerHostList", result);

    timeLogger.print("Send Docker Host List");

    return list;
}
Send list of docker hosts to client
@param {Socket} socket Socket.io socket instance
@returns {Promise<Bean[]>} List of docker hosts