add github workflow

.github/workflows/gradle.yml

@@ -0,0 +1,40 @@
+# This workflow uses actions that are not certified by GitHub.
+# They are provided by a third-party and are governed by
+# separate terms of service, privacy policy, and support
+# documentation.
+# This workflow will build a Java project with Gradle and cache/restore any dependencies to improve the workflow execution time
+# For more information see: https://help.github.com/actions/language-and-framework-guides/building-and-testing-java-with-gradle
+
+name: Java CI with Gradle
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up JDK 11
+        uses: actions/setup-java@v2
+        with:
+          java-version: '11'
+          distribution: 'temurin'
+      - name: Build with Gradle
+        uses: gradle/gradle-build-action@937999e9cc2425eddc7fd62d1053baf041147db7
+        with:
+          arguments: :free:shadowJar
+      - name: Upload a Build Artifact
+        uses: actions/upload-artifact@v2.3.1
+        with:
+          # Artifact name
+          name: plugin jar
+          # A file, directory or wildcard pattern that describes what to upload
+          path: build/libs/ajQueue*.jar
+          # The desired behavior if no files are found using the provided path.
+          if-no-files-found: error