Validate Gerrit changes on stable-2.15 with Jenkins

Change-Id: I35c47ba60c08e8d5d1f767672b5e83b7d29fea1b
(cherry picked from commit 1346eab23259f8dc4adec9cb098e2f818c9cf79d)
diff --git a/Jenkinsfile b/Jenkinsfile
new file mode 100644
index 0000000..565dd45
--- /dev/null
+++ b/Jenkinsfile
@@ -0,0 +1 @@
+gerritPipeline()