Add github action to compile JAR

.github/workflows/build.yml

@@ -0,0 +1,52 @@
+name: Build
+
+on:
+  push:
+    branches:
+      - main
+    paths-ignore:
+      - README.md
+      - .gitignore
+      - .gitattributes
+      - '**/.git/*'
+  pull_request:
+    branches:
+      - main
+    paths-ignore:
+      - README.md
+      - .gitignore
+      - .gitattributes
+      - '**/*.md'
+      - '**/.git/*'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          fetch-tags: true
+
+      - name: Setup JDK 21
+        uses: actions/setup-java@v4
+        with:
+          java-version: '21'
+          distribution: 'temurin'
+
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v4
+        
+      - name: Grant execute permission to gradlew
+        run: chmod +x gradlew
+        
+      - name: Build with Gradle
+        run: ./gradlew build
+  
+      - name: Upload Build Artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: main-build
+          path: build/libs/*.jar
+