Add Jenkinsfile for CI/CD pipeline

This Jenkinsfile sets up a simple CI/CD pipeline with three stages: 'Gradle' for building the project, 'Archive' for saving build artifacts, and 'discord' for sending build notifications. The pipeline uses npm for package management and build steps, and integrates with Discord for build result notifications.

Jenkinsfile

@@ -0,0 +1,21 @@
+pipeline {
+    agent any
+    stages {
+        stage('Gradle') {
+            steps {
+                sh 'npm install'
+                sh 'npm run build'
+            }
+        }
+        stage('Archive') {
+            steps {
+                archiveArtifacts artifacts: 'build/**', followSymlinks: false
+            }
+        }
+        stage('discord') {
+            steps {
+                discordSend description: "Build: ${BUILD_NUMBER}", showChangeset: true, result: currentBuild.currentResult, title: currentBuild.fullProjectName, webhookURL: env.discordwebhook
+            }
+        }
+    }
+}