Add more proper setup and build steps

Jenkinsfile

@@ -1,9 +1,13 @@
 pipeline {
     agent { docker { image 'node:13.10-alpine' } }
     stages {
+        stage('setup') {
+            sh npm install
+            sh export PATH=$PATH:node_modules/.bin
+        }
         stage('build') {
             steps {
-                sh 'npm --version'
+                sh 'ng build --prod'
             }
         }
     }