pipeline {
   agent any 
   stages {
     stage('Build') {
      steps {
         gitlabCommitStatus(name:"build") {
         script { 
           docker.withRegistry('Nexus URL', 'docker-pull-id') {
              app = docker.build("my-project","--my proxy options") 
           }
         }
        } 
       }
     }
     stage('Push image') {
       steps {
         script { 
           docker.withRegistry('Nexus URL', 'docker-push-id') {
           app.push("latest")
         }
        }
      }
     }
     stage('Push tag image') {
       when { buildingTag() }
        steps {
          script { 
             docker.withRegistry('Nexus URL', 'docker-pull-id')') {
               app.push("tag")
            }
          }
       }
    }
  }
}