Simple chat app (#921)

* Add file

Initial implementation

* Add file

Implementation

* 1. update readme 2. update web example 3. update code

* update readme

* remove working dir

* update

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Co-authored-by: “skzhang1” <“shaokunzhang529@gmail.com”>
Co-authored-by: Shaokun Zhang <shaokunzhang529@gmail.com>