Add 'npm start' to README

Author: Aljullu

README.md

@@ -1,6 +1,6 @@
 # React Lazy Load Image Component demo
 
-This is a demo of the `react-lazy-load-image-component` NPM package. It's not intended to be used in real life applications neither to be an example of good programming practices, but just to give an example of how to use the package `react-lazy-load-image-component` and its props.
+This is a demo of the `react-lazy-load-image-component` NPM package. It's not intended to be used in real life applications neither to be an example of good programming practices, but to give an example of how to use the package `react-lazy-load-image-component` and its props.
 
 * See the live demo in action: https://github.com/Aljullu/react-lazy-load-image-component
 
@@ -13,3 +13,4 @@ This is a demo of the `react-lazy-load-image-component` NPM package. It's not in
 
 ```bash
 $ npm i
+$ npm start