Add Jenkins pipeline

Jenkinsfile

@@ -0,0 +1,31 @@
+```groovy
+pipeline {
+    agent any
+
+    stages {
+        stage('Checkout') {
+            steps {
+                checkout scm
+            }
+        }
+
+        stage('Build') {
+            steps {
+                sh '''
+                    echo "Building project..."
+                    mkdir -p build
+                    g++ main.cpp -o build/test_app
+                '''
+            }
+        }
+
+        stage('Run') {
+            steps {
+                sh '''
+                    ./build/test_app
+                '''
+            }
+        }
+    }
+}
+```