Update Jenkinsfile

Jenkinsfile

@@ -1,5 +1,5 @@
 pipeline {
-    agent any
+    agent dockerfile true
     parameters {
     string(name: 'KAGGLE_USERNAME', defaultValue: 'alicjaszulecka', description: 'Kaggle username')
     password(name: 'KAGGLE_KEY', defaultValue:'', description: 'Kaggle Key')
@@ -21,5 +21,10 @@ pipeline {
                  }
              }
          }
+         stage('Test') {
+            steps {
+                sh 'cat etc/issue'
+            }
+         }
      }
 }