Add github actions file

.github/workflows/workflow.yml

@@ -0,0 +1,21 @@
+name: Run tests
+
+on: [push]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Set up Flutter
+      uses: subosito/flutter-action@v1
+      with:
+        flutter-version: '2.0.6'
+
+    - name: Install dependencies
+      run: flutter pub get
+
+    - name: Run tests
+      run: flutter test