Install QGIS - IT2901-24-2018/vapi GitHub Wiki
Ubuntu
sudo sh -c 'echo "deb http://qgis.org/debian xenial main" >> /etc/apt/sources.list'
sudo sh -c 'echo "deb-src http://qgis.org/debian xenial main " >> /etc/apt/sources.list'
wget -O - http://qgis.org/downloads/qgis-2017.gpg.key | gpg --import
gpg --fingerprint CAEB3DC3BDF7FB45
gpg --export --armor CAEB3DC3BDF7FB45 | sudo apt-key add -
sudo apt-get update && sudo apt-get install qgis python-qgis
Add postgis layer
Click on the elephant on the left
Under connections press New
Add a name (actually important)
Add the correct host and port and set the name of the database
Test the connection and press OK
Then connect, login and select the table you want and add.