Ability for user to switch theme


I would like to let my user switch between two themes.
I found that only the admin was able to switch the theme, and at a global level (for everyone). (ref: Howto setup permissions for plugins dir)

Would this request a lot of work?
I’m developper and could help to make this happen but I’m not too aware of how the thing works from now.

Thank you,

With the plugin https://github.com/creecros/Customizer the thema is configurable per user.

Read wiki: https://github.com/creecros/Customizer/wiki/Manage-Themes

Should explain it.