Update description in readme.

Author: ExpDev07

README.md

@@ -1,6 +1,6 @@
 # coronavirus-tracker (API)
 
-> This is a fast (< 200ms) and basic API for tracking development of the new coronavirus (COVID-19, SARS-CoV-2). It's written in python using 🍼 Flask.
+> This is a fast (< 200ms) and basic API for tracking development of the new coronavirus (COVID-19, SARS-CoV-2). It's written in python using 🍼 Flask. Supports multiple sources!
 
 ![Travis build](https://api.travis-ci.com/ExpDev07/coronavirus-tracker-api.svg?branch=master)
 [![All Contributors](https://img.shields.io/badge/all_contributors-1-orange.svg?style=flat-square)](#contributors-)