This application code consists of submodules. You can use "--recurse-submodules" flag when calling "git clone" to fetch the submodules.
More about submodules: https://git-scm.com/book/en/v2/Git-Tools-Submodules
The original repository for the backend submodule is here https://github.com/ryuumx/autocheckinapp-backend/
The original repository for the frontend submodule is here https://github.com/ykbryan/autocheckinapp-frontend