Update zmusic-ng link

README.md

@@ -38,7 +38,7 @@ Resources
     - [Writing RESTful web services with Flask](http://pyvideo.org/video/2668/writing-restful-web-services-with-flask)
     - [Practical Flask Web Development Tutorials](https://www.youtube.com/playlist?list=PLQVvvaa0QuDc_owjTbIY4rbgXOFkUYOUB)
 - Build with Flask
-    - [zmusic-ng](http://git.zx2c4.com/zmusic-ng/) - ZX2C4 Music provides a web interface for playing and downloading music files using metadata.
+    - [zmusic-ng](https://git.zx2c4.com/zmusic-ng/) - ZX2C4 Music provides a web interface for playing and downloading music files using metadata.
     - [GuitarFan](https://github.com/lowrain/GuitarFan) - guitar tab
     - [June](https://github.com/pythoncn/june) - ~~python-china.org~~
     - [Zerqu](https://github.com/lepture/zerqu) - ZERQU is a content-focused API-based platform. eg: [Python-China](https://python-china.org)