add .gitreview

A .gitreview file is required to use git review.
More information about git review
https://www.mediawiki.org/wiki/Gerrit/git-review

Change-Id: I03cbdf3a95bcf36a7388b5fa2652fd774b8f0f5b
Reviewed-on: https://gerrit.osmocom.org/68
Tested-by: Jenkins Builder
Reviewed-by: Holger Freyther <holger@freyther.de>
diff --git a/.gitreview b/.gitreview
new file mode 100644
index 0000000..628d176
--- /dev/null
+++ b/.gitreview
@@ -0,0 +1,3 @@
+[gerrit]
+host=gerrit.osmocom.org
+project=osmo-pcu