create action

add simple build action

.github/workflows/main.yml

@@ -0,0 +1,26 @@
+name: CI
+
+on:
+  push:
+    branches: [ master ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Install dependencies
+        run: yarn
+
+      - name: Build android release
+        run: cd android && ./gradlew assembleRelease
+
+      - name: Upload Artifact
+        uses: actions/upload-artifact@v1
+        with:
+          name: release
+          path: android/app/build/outputs/apk/release/app-release.apk
+
+