Install the Syncthing and Syncthing GTK on Ubuntu is not a complicated procedure, but I already did once, spent time, I went again and had forgotten. And there are several ways to, so I thought a good idea catalog here, because the next time I come directly here.
Syncthing on Ubuntu
The idea is to add the official repository in Ubuntu, so that the updates are also installed easily. This procedure also applies to Debian and Linux Mint.
sudo apt-get install curl curl -s https://syncthing.net/release-key.txt | sudo apt-key add - echo "deb http://apt.syncthing.net/ syncthing release" | sudo tee /etc/apt/sources.list.d/syncthing-release.list sudo apt-get update sudo apt-get install syncthing
Source: Web Upd8
Syncthing-GTK on Ubuntu
The idea here is to add the The PPA Web Upd8 and then install the Syncthing-GTK from it.
sudo add-apt-repository ppa:nilarimogard/webupd8 sudo apt-get update sudo apt-get install syncthing-gtk
Source: Syncthing Forum
After the facilities, you need to restart Ubuntu for everything to work correctly, otherwise the Syncthing-GTK does not detect and not running daemon. After restarting the Ubuntu is just starting the Syncthing-GTK and everything should work.
Update (01/03/2016): Apparently the secret to work is not reset, but start the Syncthing once the terminal. Simply start typing ' syncthing ', wait a little and get the Ctrl + C. Then, When starting the Syncthing-GTK it already detects the daemon.