Add CODEOWNERS (#545)

CODEOWNERS

+# Github owner file
+# List of code reviewers for TVM modules
+
+# Global reviewers
+*        @dmlc/tvm-committers
+
+# LLVM backends
+src/llvm/*          @aatluri
+
+# ROCM runtime
+src/runtime/rocm/*    @aatluri
+
+# JVM language
+jvm/*   @javelinjs
+
+# TOPI
+topi/python/topi/*  @Laurawly @Huyuwei

CONTRIBUTORS.md

@@ -18,10 +18,19 @@ Committers are people who have made substantial contribution to the project and
 - [Haichen Shen](http://homes.cs.washington.edu/~haichen/), University of Washington
 - [Ziheng Jiang](https://github.com/ZihengJiang), Fudan University
 
+Code Owners
+-----------
+[Code owners](CODEOWNERS) are people who make substantial contribution to a module
+and are qualified to lead development and review changes of the owned module.
+
+- [Aditya Atluri](https://github.com/adityaatluri) ROCM
+- [Leyuan Wang](https://github.com/Laurawly) TOPI
+- [Yuwei Hu](https://github.com/Huyuwei) TOPI
+- [Yizhi Liu](https://github.com/javelinjs) JVM package
+
 List of Contributors
 --------------------
 - [Full List of Contributors](https://github.com/dmlc/tvm/graphs/contributors)
   - To contributors: please add your name to the list.
 - [Qiao Zhang](https://github.com/zhangqiaorjc)
-- [Yizhi Liu](https://github.com/javelinjs)
 - [Jian Weng](https://github.com/were)