Added the exploit-db link

Author: mufeedvh

README.md

@@ -10,6 +10,8 @@ CVE-2019-8449 Exploit for Jira Releases Below v8.3.4
 <b>Affected Versions:</b>  2.1 - 8.3.4
 <br>
 <b>Publish Date:</b> 2019-09-11
+<br>
+<b>Exploit-DB:</b> https://www.exploit-db.com/exploits/47990
 
 # Description
 The /rest/api/latest/groupuserpicker resource in Jira before version 8.4.0 allows remote attackers to enumerate usernames via an information disclosure vulnerability.