The database is not part of the repository. When you clone the project on a different machine, you get the code, the models, the configuration, the logic, but not the actual data. This is intended.
The sqlite db that Strapi uses by default is stored in a file that sits in a folder within your repository (can’t remember the exact name, I’m on my phone right now). But that folder is listed in the .gitignore file. Again, this is intended.
If you want to transfer data between different environments, you can copy the sqlite db file manually or do an sql export/import process.