Add Jenkinsfile for plugin verification

Change-Id: I657e5f33f41c3b9b9b449437c764d4bd0f38a6bd

Jenkinsfile

diff --git a/Jenkinsfile b/Jenkinsfile
new file mode 100644
index 0000000..efd67bf
--- /dev/null
+++ b/Jenkinsfile
@@ -0,0 +1,2 @@
+pluginPipeline(formatCheckId: 'gerritforge:plugins-spanner-refdb-code-style',
+                buildCheckId: 'gerritforge:plugins-spanner-refdb-build-test')