According to official Minecraft Twitch streams they don't even know for certain they will be able to use USB to do this yet due to the consoles not allowing USB to install files. This was due to the fact that USB was used on the 360 to mod and cheat on call of duty games. So MS are reluctant to allow USB on the xbox one.
If they can't find away to allow the use of USB without compromising the security of the system then they will have to find another way to put mods on console. Maybe similar to the way bethesda does it with Fallout 4 and Skyrim