[Doc] Create CONTRIBUTING.md (apache#3180)

CONTRIBUTING.md

@@ -0,0 +1 @@
+docs/documentation/en/community/how-to-contribute_EN.md

CONTRIBUTING_CN.md

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+docs/documentation/cn/community/how-to-contribute.md

docs/documentation/cn/community/how-to-contribute.md

@@ -72,3 +72,4 @@ under the License.
 您可以下载代码，编译安装，部署运行试一试（可以参考[编译文档](../installing/compilation.md)），看看是否与您预想的一样工作。如果有问题，您可以直接联系我们，提 Issue 或者通过阅读和分析源代码自己修复。
 
 无论是修复 Bug 还是增加 Feature，我们都非常欢迎。如果您希望给 Doris 提交代码，您需要从 GitHub 上 fork 代码库至您的项目空间下，为您提交的代码创建一个新的分支，添加源项目为upstream，并提交PR。
+提交PR的方式可以参考文档 [Pull Request](./pull-request.md)。

docs/documentation/en/community/how-to-contribute_EN.md

@@ -72,3 +72,5 @@ You can also fix it yourself by reading the analysis code (of course, it's bette
 You can download the code, compile and install it, deploy and run it for a try (refer to the [compilation document] (./installing/compilation.md)) to see if it works as you expected. If you have problems, you can contact us directly, ask questions or fix them by reading and analyzing the source code.
 
 Whether it's fixing Bugs or adding Features, we're all very welcome. If you want to submit code to Doris, you need to create a new branch for your submitted code from the fork code library on GitHub to your project space, add the source project upstream, and submit PR.
+
+About how to submit a PR refer to [Pull Request] (./pull-request.md).