Try to repair docker push

Jenkinsfile

@@ -32,13 +32,16 @@ node {
          * First, the incremental build number from Jenkins
          * Second, the 'latest' tag.
          * Pushing multiple tags is cheap, as all the layers are reused. */
+         def docker_tag
          script {
             if (env.BRANCH_NAME == 'master') {
-                    app.push()
+                    docker_tag = "latest"
             } else {
-                    app.push("devel")
+                    docler_tag = "devel"
             }
          }
+         echo docker_tag
+         app.push(docker_tag)
         
         
     }