Update Readme.md

fix link to chat channel. IRC is obsolete now.

Readme.md

@@ -14,7 +14,6 @@ Coverity<a href="https://scan.coverity.com/projects/5607">
   <img alt="Coverity Scan Build Status"
        src="https://scan.coverity.com/projects/5607/badge.svg"/>
 </a>
-Gitter [![Join the chat at https://gitter.im/assimp/assimp](https://badges.gitter.im/assimp/assimp.svg)](https://gitter.im/assimp/assimp?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 <br>
 __[open3mod](https://github.com/acgessler/open3mod) is a powerful 3D model viewer based on Assimp's import and export abilities.__
 
@@ -117,8 +116,7 @@ For development discussions, there is also a (very low-volume) mailing list, _as
 
 Open Asset Import Library is a library to load various 3d file formats into a shared, in-memory format. It supports more than __40 file formats__ for import and a growing selection of file formats for export.
 
-And we also have an IRC-channel at freenode: #assetimporterlib . You can easily join us via: [KiwiIRC/freenote](https://kiwiirc.com/client/irc.freenode.net), choose your nickname and type
-> /join #assetimporterlib
+And we also have a Gitter-channel:Gitter [![Join the chat at https://gitter.im/assimp/assimp](https://badges.gitter.im/assimp/assimp.svg)](https://gitter.im/assimp/assimp?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)<br>
 
 ### Contributing ###
 Contributions to assimp are highly appreciated. The easiest way to get involved is to submit