add bcm2835-v4l2 in a new line to create /dev/video0 on boot

sudo nano /etc/modules-load.d/raspberrypi.conf

Load module to get /dev/video0 in this section

modprobe bcm2835-v4l2

For more information

sudo v4l2-ctl -d /dev/video0 --all

Install gst

yaourt -S gstreamer v4l-utils gst-plugins-bad gst-plugins-good gst-plugins-ugly --noconfirm