Update README.md

Author: Andrey Safonov

README.md

@@ -1,15 +1,22 @@
 ## nodejs-convert-file-server
 Node.js - Convert from MS Office, images to PDF, get thumbnails for file previews, optimize files for quick rendering.
 
-### Instalation
+### Installation
 
 Clone the repo and run
 
 `npm start`
 
-The server will be listening on port 9000.
+The server will be listening on port 9000. `http://localhost:9000`
 
 
 ### API Calls
 
+#### List file directory
+
+The endpoint returns all files present in the files directory in JSON format.
+
+##### HTTP Request
+`GET http://localhost:9000/files`
+