Update README.md

Ranorex mentioned

Author: RalfKoban

README.md

@@ -35,6 +35,7 @@ Please do not hijack unrelated issues, I would rather you create a new issue tha
 | [NDepend](https://www.ndepend.com/) | .ndproj, .ndrules
 | NuGet Configuration | _packages.config_
 | NuGet Manifest | .nuspec
+| Ranorex (Repositories) | .rxrep
 | [Sandcastle Help File Builder](https://github.com/EWSoftware/SHFB) Project  | .shfbproj
 | Visual Build | .bld
 | Visual Studio C++ Project | .vcxproj