added docker file

Jenkinsfile

@@ -8,6 +8,7 @@ pipeline {
     
     environment {
         SONAR_AUTH_TOKEN = credentials('SONAR_AUTH_TOKEN') // Assumes you have stored your token in Jenkins Credentials
+        
     }
     
     stages {
@@ -56,5 +57,18 @@ pipeline {
                 sh 'mvn clean package -DskipTests'
             }
         }
-    }    
+        stage('Build & push Docker Image') {
+            
+            steps {
+                script {
+                    withDockerRegistry('Docker') {
+                        sh "docker build -t prasannakumarsinganamalla431/petclinic:${BUILD_NUMBER} ."
+
+
+                    }
+                }
+            }    
+        }
+    }   
+
 }