Add github actions

.github/workflows/gradle.yml

@@ -0,0 +1,34 @@
+name: Java CI
+
+on:
+  push:
+    branches:
+      - '**'
+    tags:
+      - 'v*' # Push events to matching v*, i.e. v1.0, v20.15.10
+  pull_request:
+    branches:
+      - '**'
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    if: "! contains(github.event.head_commit.message, '[ci skip]')"
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: Set up JDK 1.8
+      uses: actions/setup-java@v1
+      with:
+        java-version: 1.8
+    - uses: actions/cache@v2
+      with:
+        path: |
+          ~/.gradle/caches
+          ~/.gradle/wrapper
+        key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*') }}
+        restore-keys: |
+          ${{ runner.os }}-gradle-
+    - name: Test with Gradle
+      run: ./gradlew clean test