As a senior Java backend engineer with experience in Spring Boot, MySQL, and Docker, you are already familiar with the benefits of version control for managing code changes and collaborating with other developers. Now, it's time to set up a GitHub repository and start using version control with your RESTful API.

GitHub is a popular platform for hosting Git repositories and managing code projects. It provides a user-friendly interface for tracking changes, creating branches, and merging code changes.

To get started, follow these steps:

1. Sign up for a GitHub account at github.com.
2. Create a new repository by clicking on the 'New' button.
3. Give your repository a name and choose whether it should be public or private.
4. Initialize the repository with a README file, which will serve as the starting point for your project.
5. Once the repository is created, you can clone it to your local machine using the git clone command.

1$ git clone <repository url>

6. Now you have a local copy of your repository. You can start by adding your existing code files to the repository using the git add command.

1$ git add <file1> <file2> ...

7. Commit your changes using the git commit command.

1$ git commit -m 'Initial commit'

8. Push your changes to the remote repository using the git push command.

1$ git push origin master

By following these steps, you have successfully set up a GitHub repository and pushed your initial code changes.

GitHub also provides additional features such as pull requests, which allow you to review and merge code changes from other developers, and issues, which can be used to track and manage tasks, bugs, and feature requests.

Now that you have your code on GitHub, you can easily showcase your skills and projects to potential employers by sharing the repository URL on your resume or portfolio.

Keep in mind that when working with a team on a project, it's important to follow best practices for collaborating on GitHub, such as creating branches for separate features or bug fixes, and regularly pulling changes from the main repository to stay up to date with the latest code.

Start using GitHub for version control today, and take your RESTful API development to the next level!