added 'SSRF Tips'

- signed-off-by: trimstray <trimstray@gmail.com>

README.md

@@ -552,6 +552,7 @@ Linux Security Expert</b></a> - trainings, howtos, checklists, security tools an
 &nbsp;&nbsp;:small_orange_diamond: <a href="http://html5sec.org/"><b>HTML5 Security Cheatsheet</b></a> - a collection of HTML5 related XSS attack vectors.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://gtfobins.github.io/"><b>GTFOBins</b></a> - list of Unix binaries that can be exploited by an attacker to bypass local security restrictions.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://guif.re/"><b>Guifre Ruiz Notes</b></a> - collection of security, system, network and pentest cheatsheets.<br>
+&nbsp;&nbsp;:small_orange_diamond: <a href="http://blog.safebuff.com/2016/07/03/SSRF-Tips/index.html"><b>SSRF Tips</b></a> - a collection of SSRF Tips.<br>
 </p>
 
 ##### :black_small_square: Bounty programs