安装的plugin：
- kubernetes:1.7.1
- workflow-aggregator:2.5
- workflow-job:2.21
- credentials-binding:1.13
- git:3.6.4
- gitlab-hook:1.4.2
- ansicolor:0.5.2
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create a free-style project
token 是我自己随机生成的字符串
gitlab中：
settings->Integrations->Add webhook
http://jenkins.gcloud.srcb.com/job/test-git/build?token=9bcd9285c12a2e9aa8bf48732c7a76abc1e45ea2
trigger 勾选 Push events