I was talking to my friend and she said she had minecraft on Xbox 360 which made me wonder if I could play minecraft on Xbox one with her.
Sadly no. This is Xbox's way of making you pay money to buy their new console. It sucks I know. The reason this is the case is because the graphics and code for the Xbox 360 and Xbox 1 games are different. So therefore the Xbox 360 cannot compile Xbox 1 code. Which in turn means you cannot play multiplayer games with one person on an Xbox 1 and one person on an Xbox 360. So unfortunately you or your friend would have to buy the other console.