Added Gitter badge

README.md

@@ -42,4 +42,8 @@ $ ./daemon/kresd [working_directory]
 See the documentation at [knot-resolver.readthedocs.org][doc].
 
 [depends]: http://knot-resolver.readthedocs.org/en/latest/build.html
-[doc]: http://knot-resolver.readthedocs.org/en/latest/index.html
\ No newline at end of file
+[doc]: http://knot-resolver.readthedocs.org/en/latest/index.html
+
+### Contacting us
+
+[![Join the chat at https://gitter.im/CZ-NIC/knot-resolver](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/CZ-NIC/knot-resolver?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)