Add GitHub workflow to run tests on pushes to main

.github/workflows/android.yml

@@ -0,0 +1,32 @@
+name: Android CI
+
+on:
+  push:
+    branches: [ main ]
+
+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: Grant execute permission for gradlew
+      run: chmod +x gradlew
+    - name: Build with Gradle
+      run: ./gradlew assemblePlayDebug assemblePlayDebugAndroidTest assemblePlayDebugUnitTest
+    - name: Run unit tests
+      run: ./gradlew testPlayDebugUnitTest
+    - name: Add auth for flank
+      env:
+        GCLOUD_KEY: ${{ secrets.GCLOUD_KEY }}
+        GCLOUD_DIR: "$HOME/.config/gcloud/"
+      run: |
+        mkdir -p "$GCLOUD_DIR"
+        echo "$GCLOUD_KEY" | base64 --decode > "$GCLOUD_DIR/application_default_credentials.json"
+    - name: Run UI tests
+      run: ./gradlew runFlank