update readme

README.md

@@ -1,12 +1,24 @@
 # Image Processing API
 
+A Simple API built using express framework that allows to display images on a web page with the size of the image is set via URL parameters.
+
+## Things this api do
+
 - Resizing images
 - Serving cached images
 
-To start server: `npm run start:server`
+## To run the server
+
+`npm run start:server`
+
+## To build the server
+
+`npm run build`
+
+## To run tests
 
-To build: `npm run build`
+`npm run test`
 
-To test: `npm run test`
+## Endpoint to test the api
 
 Endpoint: `http://localhost:4000/api/images?filename=fjord&width=200&height=400`