Adding ESLint config -- run yarn lint on prebuild

README.md

@@ -22,6 +22,10 @@ Clone this repository and install [yarn](https://yarnpkg.com/getting-started/ins
   - Installs node packages
 - `yarn dev`
   - Serves local dev at [localhost:3000](http://localhost:3000)
+- `yarn lint`
+  - Runs [ESLint](https://eslint.org/) validations on source JS
+  - ESLint errors will fail your builds so check your code before pushing
+  - Install the [ESLint plugin for Visual Studio Code](https://marketplace.visualstudio.com/items?itemName=dbaeumer.vscode-eslint&ssr=false#overview)
 - `yarn build && yarn start`
   - Create an optimized Next.js production build and serve it locally
 - `yarn build && yarn export`