By now rails new has already initialised the local git repository and created an initial commit for you. This step pushes that commit to the GitHub repository you created in the previous step.
If you used gh repo create renuo/[project-name] --private --source=. --remote=origin, the origin remote is already set. Otherwise, add it:
git remote add origin git@github.com:renuo/[project-name].gitThen push:
git push -u origin main