minor fix

Jenkinsfile

@@ -35,9 +35,10 @@ pipeline {
             steps {
                 script {
                     // Build with commit hash tag
+                    APP_GIT_HASH = sh(script: 'git rev-parse --short HEAD', returnStdout: true).trim()
                     sh '''
                         docker build -t ${DOCKER_HUB_USERNAME}/${IMAGE_NAME}:latest .
-                        docker tag ${DOCKER_HUB_USERNAME}/${IMAGE_NAME}:latest ${DOCKER_HUB_USERNAME}/${IMAGE_NAME}:${GIT_COMMIT_HASH}
+                        docker tag ${DOCKER_HUB_USERNAME}/${IMAGE_NAME}:latest ${DOCKER_HUB_USERNAME}/${IMAGE_NAME}:${APP_GIT_HASH}
                     '''
                 }
             }
@@ -45,9 +46,10 @@ pipeline {
         
         stage('Push to Docker Hub') {
             steps {
+                APP_GIT_HASH = sh(script: 'git rev-parse --short HEAD', returnStdout: true).trim()
                 sh '''
                     # Push both tags
-                    docker push ${DOCKER_HUB_USERNAME}/${IMAGE_NAME}:${GIT_COMMIT_HASH}
+                    docker push ${DOCKER_HUB_USERNAME}/${IMAGE_NAME}:${APP_GIT_HASH}
                     docker push ${DOCKER_HUB_USERNAME}/${IMAGE_NAME}:latest
                 '''
             }