Unity collaborate, Add files outside of Asset Folder

Hello, I wanted to sync a project between my desktop PC at home and my work laptop.

The problem however is that I cant figure out how to add an external folder to the files to sync. I have a folder besides the assets folder with all the data like textures, sounds, icons, etc.

How do I add this folder so that it is synced on both computers?

I know that I have to edit the .collabignore file , but what do i have to add?

Thanks in advande

I definitely need a solution to this problem, too.

How is it possible to use folders and files outside the project-folder as links without COPYing them?

Everyone has a folderstructure with common, reusable assets like classes, images and objects, which should stay in their place and should not be copied into folders of special projects, where changes only affect the local copy.

I tried adding a link to the file or folder into the project asset-folder, but unity doesn’t follow the link.
I can add an external file as a link in the visual-studio-project and compile it without errors, but Unity then is not able to start the scene, although the vs-project compiled it.

Is this maybe only possible with class library assemblies or something similar?

Anyone figure out a solution for this yet?

Apparently this has been added to collab preview in Dec 2019:

this feature has actually been added in the v2.0-preview.17 package of Collaborate, which you can update to from the Package Manager and choosing to see preview packages from that window’s option menu. From there, make sure that the folders you want to include are not in the modified .collabignore file so that Collaborate can pick them up properly.

https://forum.unity.com/threads/adding-files-to-collab-outside-of-the-assets-folder.450845/