Containerize an existing web application so that development, testing, and deployment environments are more consistent. The Docker setup should be easy for a new developer to run, should not expose secrets, and should include practical troubleshooting notes for common environment problems. The successful freelancer will be expected to work independently, share progress at agreed checkpoints, and raise questions early when a requirement needs clarification. All submitted work should be original, well organized, and ready for practical use after reasonable review.