added hypergrid (#70)

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
diff --git a/source/users.html.markdown b/source/users.html.markdown
index a606e3b..46726e7 100644
--- a/source/users.html.markdown
+++ b/source/users.html.markdown
@@ -48,6 +48,7 @@
 * [FiberCloud](http://www.fibercloud.com)
 * [FortaCloud](http://www.fortacloud.co)
 * [Heinlein Support GmbH](http://www.heinlein-support.de)
+* [Hypergrid SRL](https://www.hypergrid.it)
 * [Imperial College](http://www.imperial.ac.uk/computing)
 * [InhouseIT](http://www.inhouseit.com)
 * [INRIA](http://inria.fr)