Wall-Mounted Filament Roller Guide

I really love [Holspeed's Ender 3 Pro filament guide](https://www.thingiverse.com/thing:3052488), but when I moved my filament spool to the wall, I wanted to add some brackets to help guide it down to my printer.

Their very helpful assembly instructions:

> You will need to print:
>
> 1 - bracket,
>
> 1 - ring - (print ring.stl first, if it isn't tight enough then ring-sm.stl is slightly smaller inside).
>
> 2 - spacers
>
> Plus you will need:
>
> 1 - 608 bearing (probably the most commonly available bearing, used for skateboard wheels and other things).
>
> 1 - M4 x 16mm bolt (spare part with my Ender 3, hopefully yours too).
>
> Assembly (the photos will assist):
>
> 1) Lay the ring on a flat surface and press the bearing all the way in - if you feel it isn't on tight enough then print ring-sm and use that one.
>
> 2) Push a spacer into each side of the bearing
>
> If you don't want to pull the filament out of your hotend do step 3 last.
>
> 3) F