How to set a new root in GIT?

Question

git

Greetings!
The project with the repository has moved to a subfolder.
It was

/folder
   .git
   index.html
   app.js

became

/folder
   /app 
      .git
      index.html
      app.js

you need to somehow create a repository in the /folder folder, which will capture the existing one in the /folder/app subfolder.
Is this possible?

Answer 1

git-scm.com/book/en/%D0%98%D0%BD%D1%81%D1%82%D1%80...