Add USER parameter to the form of creating a new app

[AmadeusGraves]

In docker exists one parameter that you allowed to create a new user when you execute docker run, the parameter is -u, this parameter is not mapped in the form.

This parameter is necesary for docker images like filebrowser, because this image has this error.

filebrowser/filebrowser#704

[AmadeusGraves]

Sorry for my English, it isn't my first language.

[AmadeusGraves]

i search and i find in this url a better explanation of this issue

https://jtreminio.com/blog/running-docker-containers-as-current-host-user/

and a possible temporary solution explained doesn't work sadly