Git and prestashop 1.7.6

[crimba]

I install prestashop 1.7.6 when, I do "git add ." but i recive this error:

hint: You've added another git repository inside your current repository.
hint: Clones of the outer repository will not contain the contents of
hint: the embedded repository and will not know how to obtain it.
hint: If you meant to add a submodule, use:
hint: 
hint:   git submodule add <url> modules/psaddonsconnect/vendor/react/promise
hint: 
hint: If you added this path by mistake, you can remove it from the
hint: index with:
hint: 
hint:   git rm --cached modules/psaddonsconnect/vendor/react/promise
hint: 
hint: See "git help submodule" for more information.
 

modules psaddonsconnect have different repo on vendor. I can delete all repo on psaddonsconnect?