Update License Badge

Author: krayong

README.md

@@ -26,7 +26,7 @@
 [![contributions welcome](https://img.shields.io/badge/contributions-welcome-blue.svg?style=flat)](https://github.com/krayong/Study_Partner/issues)
 <br>
 
-[![MIT License](https://img.shields.io/apm/l/atomic-design-ui.svg?)](https://github.com/tterb/atomic-design-ui/blob/master/LICENSEs)
+[![License](https://img.shields.io/badge/License-Apache_2.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
 [![GitHub release](https://img.shields.io/github/release/krayong/Study_Partner)](https://github.com/krayong/Study_Partner/releases/) 
 [![GitHub issues](https://img.shields.io/github/issues/krayong/Study_Partner?style=plastic)](https://github.com/krayong/Study_Partner/issues)
 [![GitHub pull-requests](https://img.shields.io/github/issues-pr/krayong/Study_Partner)](https://github.com/krayong/Study_Partner/pulls/)