Adding back SUMMARY.md file

[eric-lidong]

Description

In the recent PR to Merlin, the SUMMARY.md file is removed from the docs. While it does not affect the overall CaraML docs on gitbook, this Merlin specific MD file was added to make sure Merlin docs can work standalone with gitbook, similar to how Turing and Turing XP docs are gitbook compatible. e.g. Users who uses Merlin/Turing/Turing XP alone, outside of the CaraML setting, can also use gitbook to refer to the docs.

Modifications

Adding back the SUMMARY.md file and updated to conform with the new document structure.

Tests

Checklist

• Added PR label
• Added unit test, integration, and/or e2e tests
• Tested locally
• Updated documentation
• Update Swagger spec if the PR introduce API changes
• Regenerated Golang and Python client if the PR introduces API changes

Release Notes

[leonlnj]

thanks lgtm

[leonlnj]

I think you can ignore the errors, AFAIK merlin ci cant run from forked repo, the dev usually create a branch from the main repo