Update docs?

[ekevu123]

Would it be possible to update the docs for using it with a volume?

I find two points helpful to add:

1. Inside Syncthing, the path is /media, although the mountpoint is /mnt (I mixed that up previously and it took me time to figure this out)
2. The mountpoint needs to have 777 rights

I'd appreciate that!

[joseph]

I think that information is the same across apps . The first part is here - https://docs.cloudron.io/volumes/#add . The second part should be added ( cc @girish)