change ci from travis-ci to github actions

.github/workflows/ci.yaml

@@ -0,0 +1,33 @@
+name: Java CI
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Set up JDK 1.8
+        uses: actions/setup-java@v1
+        with:
+          java-version: 1.8
+
+      - name: Cache Gradle packages
+        uses: actions/cache@v2
+        with:
+          path: |
+            ~/.gradle/caches
+            ~/.gradle/wrapper
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+
+      - name: Test
+        run: ./gradlew test
+
+      - name: Report
+        run: ./gradlew jacocoTestReport coveralls
+        env:
+          COVERALLS_REPO_TOKEN: ${{secrets.COVERALLS_REPO_TOKEN}}