Update CONTRIBUTING.md

Author: kevinongko

CONTRIBUTING.md

@@ -5,7 +5,8 @@ When contributing to this repository, please first discuss the change you wish t
 If you intend to change the public API, or make any non-trivial changes to the implementation, we recommend filing an issue. This lets us reach an agreement on your proposal before you put significant effort into it.
 
 ## Javascript style guides
-Javascript must adhere to [Vue.js official recommended style](https://github.com/vuejs/eslint-plugin-vue).
+- Javascript must adhere to [Vue.js official recommended style](https://github.com/vuejs/eslint-plugin-vue).
+- Lint command: `npm run lint`.
 
 ## DocBlock
 Every function, methods, computed properties, props should have a docblock to explain what it does