Update Jenkinsfile

Jenkinsfile

@@ -6,11 +6,11 @@ node{
         }
 
         stage('Build image') {
-            app = docker.build ("test")
+            app = docker.build ("debian:buster")
         }
 
         stage('Test image') {
-            docker.image('test').withRun('-p 81:81') { c -> 
+            docker.image('debian:buster').withRun('-p 81:81') { c -> 
             
             
             sh 'docker ps'