Root owner of uploaded files on docker-volume

Hi Everyone,
I use docker-volumes in my app. I manage virtual machine (ubuntu) with user: “SOME_USER” but I can see that uploaded files in mounted volume folder belong to root. Is it possible to change the owner of uploaded files from root to SOME_USER ? Probably this is more directly docker issue, but maybe you can help anyway ?

PS: Big “Thank you” for Open Analytics for your great job on ShinyProxy project.