Hi and welcome to the Strapi Community @Bespalov-D-A 
That depends how you setup config/database.js
By default that is setup to use sqlite.
And by default this file is in gitignore so it would not be sent to github.
Check the file to make sure you configured it to use postgres.
Also if it was a local postgres the data would not be copied over as it’s in your local postgres and not in the remote one