qBittorrent (Linux/Mac/Win)

# qBittorrent Stable
sudo add-apt-repository ppa:hydr0g3n/ppa

# qBittorrent Unstable (For testing)
sudo add-apt-repository ppa:hydr0g3n/qbittorrent-unstable

Then install qBittorrent by doing this:

sudo apt-get update && sudo apt-get install qbittorrent