I hope so. Otherwise its pointless for me to continue playing GTA V on the Xbox 360.
You can transfer from the Xbox 360 to Xbox One, but it is a one time process.
What actually happens is that a copy is made of your Xbox 360 profile at the point it is transferred. Any future progress made on the 360 profile does not reflect on the Xbox One profile. They will both be independent of each other.
The process is detailed on Rockstar's official site.