Add the Jenkinsfile that's currently being used in ci.j.o to the repo

Jenkinsfile

@@ -0,0 +1,40 @@
+#!groovy
+
+/* Only keep the X most recent builds. */
+properties([[$class: 'BuildDiscarderProperty', strategy: [$class: 'LogRotator',
+                                                          numToKeepStr: '50',
+                                                          artifactNumToKeepStr: '20']]])
+
+stage 'Build'
+node('docker') {
+    checkout scm
+    withMavenEnv {
+        sh 'mvn clean package'
+        step([$class: 'ArtifactArchiver', artifacts: '**/target/*.war', fingerprint: true])
+    }
+
+}
+
+
+/* This code shame-lessly copied and pasted from some Jenkinsfile code abayer
+   wrote for the jenkinsci/jenkins project */
+void withMavenEnv(List envVars = [], def body) {
+    // The names here are currently hardcoded for my test environment. This needs
+    // to be made more flexible.
+    // Using the "tool" Workflow call automatically installs those tools on the
+    // node.
+    String mvntool = tool name: "mvn3.3.3", type: 'hudson.tasks.Maven$MavenInstallation'
+    String jdktool = tool name: "jdk7_80", type: 'hudson.model.JDK'
+
+    // Set JAVA_HOME, MAVEN_HOME and special PATH variables for the tools we're
+    // using.
+    List mvnEnv = ["PATH+MVN=${mvntool}/bin", "PATH+JDK=${jdktool}/bin", "JAVA_HOME=${jdktool}", "MAVEN_HOME=${mvntool}"]
+
+    // Add any additional environment variables.
+    mvnEnv.addAll(envVars)
+
+    // Invoke the body closure we're passed within the environment we've created.
+    withEnv(mvnEnv) {
+        body.call()
+    }
+}