Add gerrit settings

Make it simple to setup and use this repo with 'git review' command.

Change-Id: Ic03e19e2bab46ae2383504cf26e3d7e29d361f05
diff --git a/.gitreview b/.gitreview
new file mode 100644
index 0000000..afddc7b
--- /dev/null
+++ b/.gitreview
@@ -0,0 +1,3 @@
+[gerrit]
+host=gerrit.osmocom.org
+project=osmo-hlr