Add Jenkinsfile example + wrap wording in README.md

Author: gilesgas

README.md

@@ -1,7 +1,13 @@
 # simple-java-maven-app
 
-This repository is for the [Using Jenkins to build a Java/Maven project]( https://jenkins.io/doc/tutorials/using-jenkins-to-build-a-java-maven-project/) tutorial in the [Jenkins User Documentation](https://jenkins.io/doc/).
+This repository is for the [Using Jenkins to build a Java/Maven project]( https://jenkins.io/doc/tutorials/using-jenkins-to-build-a-java-maven-project/)
+tutorial in the [Jenkins User Documentation](https://jenkins.io/doc/).
 
-The repository contains a simple Java application which outputs the string "Hello world!" and is accompanied by a unit test to check that the main application works as expected.
+The repository contains a simple Java application which outputs the string
+"Hello world!" and is accompanied by a unit test to check that the main
+application works as expected.
 
-The `jenkins` directory contains an example of the `Jenkinsfile` (i.e. Pipeline) you'll be creating yourself during the tutorial and the `scripts` directory contains a shell script with commands that are executed when Jenkins processes the "Deliver" stage of your Pipeline.
+The `jenkins` directory contains an example of the `Jenkinsfile` (i.e. Pipeline)
+you'll be creating yourself during the tutorial and the `scripts` directory
+contains a shell script with commands that are executed when Jenkins processes
+the "Deliver" stage of your Pipeline.

jenkins/Jenkinsfile

@@ -0,0 +1,25 @@
+pipeline {
+    agent {
+        docker {
+            image 'maven:3-alpine'
+            args '-v /root/.m2:/root/.m2'
+        }
+    }
+    stages {
+        stage('Build') {
+            steps {
+                sh 'mvn -B -DskipTests clean package'
+            }
+        }
+        stage('Test') {
+            steps {
+                sh 'mvn test'
+            }
+        }
+        stage('Deliver') {
+            steps {
+                sh './jenkins/scripts/deliver.sh'
+            }
+        }
+    }
+}