Merge pull request #187 from JinHai-CN/0.5.1

Update README.md

Former-commit-id: 75f01ad3b88922f6f598ef2ddb8024b867a464a3

README.md

 
 ![Milvuslogo](https://github.com/milvus-io/docs/blob/master/assets/milvus_logo.png)
 
-
+[![Slack](https://img.shields.io/badge/Join-Slack-orange)](https://join.slack.com/t/milvusio/shared_invite/enQtNzY1OTQ0NDI3NjMzLWNmYmM1NmNjOTQ5MGI5NDhhYmRhMGU5M2NhNzhhMDMzY2MzNDdlYjM5ODQ5MmE3ODFlYzU3YjJkNmVlNDQ2ZTk)
 ![LICENSE](https://img.shields.io/badge/license-Apache--2.0-brightgreen)
 ![Language](https://img.shields.io/badge/language-C%2B%2B-blue)
 [![codebeat badge](https://codebeat.co/badges/e030a4f6-b126-4475-a938-4723d54ec3a7?style=plastic)](https://codebeat.co/projects/github-com-jinhai-cn-milvus-master)
-![Release](https://img.shields.io/badge/release-v0.5.0-orange)
-![Release_date](https://img.shields.io/badge/release_date-October-yellowgreen)
+![Release](https://img.shields.io/badge/release-v0.5.1-yellowgreen)
+![Release_date](https://img.shields.io/badge/release%20date-November-yellowgreen)
 
 [中文版](README_CN.md) 
 
@@ -16,7 +16,7 @@ Milvus is the world's fastest similarity search engine for massive-scale feature
 
 For more detailed introduction of Milvus and its architecture, see [Milvus overview](https://www.milvus.io/docs/en/aboutmilvus/overview/).
 
-Milvus provides stable [Python](https://pypi.org/project/pymilvus/), [Java](https://milvus-io.github.io/milvus-sdk-java/javadoc/io/milvus/client/package-summary.html) and C++ APIs. 
+Milvus provides stable [Python](https://github.com/milvus-io/pymilvus), [Java](https://github.com/milvus-io/milvus-sdk-java) and C++ APIs. 
 
 Keep up-to-date with newest releases and latest updates by reading Milvus [release notes](https://www.milvus.io/docs/en/release/v0.5.0/).
 
@@ -46,7 +46,7 @@ Please read our [roadmap](https://milvus.io/docs/en/roadmap/) for upcoming featu
 
 Contributions are welcomed and greatly appreciated. Please read our [contribution guidelines](CONTRIBUTING.md) for detailed contribution workflow. This project adheres to the [code of conduct](CODE_OF_CONDUCT.md) of Milvus. By participating, you are expected to uphold this code.
 
-We use [GitHub issues](https://github.com/milvus-io/milvus/issues/new/choose) to track issues and bugs. For general questions and public discussions, please join our community.
+We use [GitHub issues](https://github.com/milvus-io/milvus/issues) to track issues and bugs. For general questions and public discussions, please join our community.
 
 ## Join our community