Add Docker eBook reference

[bobbyiliev]

Adding a link to the Docker eBook:

https://github.com/bobbyiliev/introduction-to-docker-ebook

[what-the-diff]

PR Summary

• Refreshed Documentation
  The links in the README.md file have been updated to ensure they point to the most accurate and up-to-date resources. This includes:
  • An added link introducing Docker
  • An updated link for Git and GitHub introduction
  • An additional link introducing Terraform
  • Yet another link added with an introduction to Linux

These changes are valuable as they provide the team with correct resources and keep everyone on the same page about the tools we use.