move contributing doc to project root

Author: lihebi

README.md

@@ -47,3 +47,12 @@ npx prisma migrate dev
 ```
 
 This command is also needed after the database schema is changed.
+
+## Contributing
+
+CodePod is open source under MIT license. Feel free to contribute! We can make
+it better together. You can contribute by opening an issue, discussion, or
+submit a pull request. Please use [Prettier](https://prettier.io/) (e.g., [its
+VSCode
+plugin](https://marketplace.visualstudio.com/items?itemName=esbenp.prettier-vscode))
+to format your code before checking in.

api/README.md

@@ -80,12 +80,3 @@ node-pty) due to missing development packages. On Ubuntu install:
 ```
 sudo apt install -y make python build-essential
 ```
-
-## Contributing
-
-CodePod is open source under MIT license. Feel free to contribute! We can make
-it better together. You can contribute by opening an issue, discussion, or
-submit a pull request. Please use [Prettier](https://prettier.io/) (e.g., [its
-VSCode
-plugin](https://marketplace.visualstudio.com/items?itemName=esbenp.prettier-vscode))
-to format your code before checking in.