安装Dash to Dock：
git clone https://github.com/micheleg/dash-to-dock.git cd dash-to-dock/ make make install
重启。
设置：
参考：
https://askubuntu.com/questions/897340/how-to-move-the-ubuntu-gnome-launcher-to-the-desktop
https://micheleg.github.io/dash-to-dock/download.html
