use cases based on OpenMLDB

We are calling the community for the contribution to help build more use cases based on OpenMLDB. The use cases can be machine learning applications, as well as other cool stuffs from your idea :-)

You may refer to our existing use cases for reference.
https://openmldb.ai/docs/en/main/use_case/index.html
https://openmldb.ai/docs/zh/main/use_case/index.html

Review the existing use cases at https://openmldb.ai/docs/en/main/use_case/index.html to understand the format and scope. Create a new use case document, likely in the documentation directory, demonstrating a machine learning application or innovative idea using OpenMLDB. Ensure the use case is well-structured and includes necessary code examples or explanations.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.