Jenkinsfile: init adding Jenkinsfile (pingcap#3249)

Author: iamxy

Jenkinsfile

@@ -0,0 +1,11 @@
+#!groovy
+
+node {
+    def TIDB_TEST_BRANCH = "master"
+    def TIKV_BRANCH = "master"
+    def PD_BRANCH = "master"
+
+    fileLoader.withGit('git@github.com:pingcap/SRE.git', 'master', 'github-iamxy-ssh', '') {
+        fileLoader.load('jenkins/ci/pingcap_tidb_branch.groovy').call(TIDB_TEST_BRANCH, TIKV_BRANCH, PD_BRANCH)
+    }
+}