fix: readme file

Signed-off-by: Xinwei Xiong(cubxxw) <3293172751nss@gmail.com>

README.md

@@ -7,16 +7,13 @@
 
 ## What is Open-IM-Server
 
+> **Note**
 > English | [中文](./README_zh.md)
 
 Open source Instant Messaging Server
-
 Instant messaging server. Backend in pure Golang, wire transport protocol is JSON over websocket.
-
 Everything is a message in Open-IM-Server, so you can extend custom messages easily, there is no need to modify the server code.
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 Using microservice architectures, Open-IM-Server can be deployed using clusters.
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 By deployment of the Open-IM-Server on the customer's server, developers can integrate instant messaging and real-time network capabilities into their own applications free of charge and quickly, and ensure the security and privacy of business data.
 
 ## Features
@@ -156,6 +153,9 @@ all services build success
 
 Contributions to this project are welcome! Please see [CONTRIBUTING.md](./CONTRIBUTING.md) for details.
 
+## Who are using Open-IM-Server
+The [user case studies](https://github.com/OpenIMSDK/community/blob/main/ADOPTERS.md) page includes the user list of the project. You can leave a [📝comment]() to let us know your use case.
+
 ## ⚠️ Announcement
 
 Dear users of the OpenIM repository, we are pleased to announce that we are currently undergoing a major overhaul to improve our service quality and user experience. We will be using the [errcode](https://github.com/OpenIMSDK/Open-IM-Server/tree/errcode) branch to make extensive updates and improvements to the main branch, ensuring that our code repository is in optimal condition.