Added Gitter link

Author: radarhere

index.html

@@ -92,7 +92,7 @@ <h3><a href=
       notes</a> and more.</p>
 
       <h3>Discussion</h3>
-      <p>Discussion occurs on <a href="https://github.com/python-pillow/Pillow/issues">GitHub</a>, <a href="https://stackoverflow.com/questions/tagged/python-imaging-library">Stack Overflow</a> and <a href="irc://irc.freenode.net#pil">IRC</a>.</p>
+      <p>Discussion occurs on <a href="https://github.com/python-pillow/Pillow/issues">GitHub</a>, <a href="https://stackoverflow.com/questions/tagged/python-imaging-library">Stack Overflow</a>, <a href="https://gitter.im/python-pillow/Pillow">Gitter</a> and <a href="irc://irc.freenode.net#pil">IRC</a>.</p>
       <h3>More</h3>
       <p>Also check out <a href="http://python-pillow.org/pillow-perf">Pillow Perf</a></p>
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