Add badge to Bugzilla

Author: wilzbach

README.md

@@ -2,6 +2,7 @@
 ===============================================================
 
 [![GitHub tag](https://img.shields.io/github/tag/dlang/dlang.org.svg?maxAge=86400)](https://github.com/dlang/dlang.org/releases)
+[![Bugzilla Issues](https://img.shields.io/badge/issues-Bugzilla-green.svg)](https://issues.dlang.org/buglist.cgi?component=dlang.org&list_id=220150&product=D&resolution=---)
 [![Issue Stats](https://img.shields.io/issuestats/p/github/dlang/dlang.org.svg?maxAge=2592000)](http://www.issuestats.com/github/dlang/dlang.org)
 [![license](https://img.shields.io/github/license/dlang/dlang.org.svg)](https://github.com/dlang/dlang.org/blob/master/LICENSE.txt)