Monochrome: Add workflow

.github/workflows/ci.yml

@@ -0,0 +1,47 @@
+name: CI
+
+on:
+  workflow_dispatch:
+  pull_request:
+    branches:
+      - master
+    paths-ignore:
+      - 'README.md'
+      - 'assets/**'
+  push:
+    branches:
+      - master
+
+jobs:
+  build-and-test-jvm:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: gradle/wrapper-validation-action@v1
+
+      - name: create and checkout branch
+        # push events already checked out the branch
+        if: github.event_name == 'pull_request'
+        run: git checkout -B ${{ github.head_ref }}
+
+      - name: set up JDK 11
+        uses: actions/setup-java@v2
+        with:
+          java-version: 11
+          distribution: "temurin"
+          cache: 'gradle'
+
+      - name: Build debug APK and run jvm tests
+        run: ./gradlew assembleDebug testDebugUnitTest --stacktrace -DskipFormatKtlint
+
+      - name: Upload APK
+        uses: actions/upload-artifact@v2.3.1
+        with:
+          name: app
+          path: app/build/outputs/apk/debug/*.apk
+
+      - name: Download a Build Artifact
+        uses: actions/download-artifact@v2.1.0
+        with:
+         name: app
+         path: app/build/outputs/apk/debug/*.apk