Add GitHub action and remove Travis config

Author: michaelschattgen

.github/workflows/build-app-workflow.yaml

@@ -0,0 +1,10 @@
+name: Build
+on: [pull_request, push]
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout the code
+        uses: actions/checkout@v2
+      - name: Build the app
+        run: ./gradlew build