How do you move code from lower environments to higher environments (dev, staging, prod) in GitHub? What practices do you follow to maintain code across environments?

A common practice is to use a Git branching model such as GitFlow or trunk-based development. Feature work happens in feature branches that merge into a develop branch. The develop branch represents the next release and is continuously integrated. When the code is ready for staging, a release branch is created from develop and deployed to a staging environment via a CI pipeline (e.g., GitHub Actions). After testing, the release branch is merged into main (or master) and deployed to production. Each environment has its own configuration files or environment variables, and the CI pipeline injects the correct values during deployment. Automated tests run at each stage: unit tests on every commit, integration tests on develop, and end‑to‑end tests on staging. Using infrastructure-as-code (Terraform, CloudFormation) ensures that the environments are reproducible. Finally, version tags on Git commits provide a clear audit trail of what code ran in each environment.