adjustable prusa i3 x motor mount

i needed a belt tensioner for my prusa but the other ones needed extra parts, or are addons, so i remixed this so it is simple to adjust the belt tension
comment if you need the holes longer
print it with more shells because it needs to be strong, maybe around 4-5
i re uploaded the file, i extended the holes badly, if you were one of the 3 first downloaders, you should re download it