Collabora Docker doesn't start at server's boot

Hi all,
I’m using Collabora Docker and it’s working perfectly. Despite the launching parameter --restart always, The docker doesn’t start at server’s reboot, but when I launch “docker ps”, the docker image starts at this moment (less than a second in the column). It’s boring to relaunch collabora manually, so anyone knows the reason and the solution to prevent this problem ? Thanks for the future answers !