add build workflow

.github/workflows/build.yml

@@ -0,0 +1,37 @@
+name: build
+
+on: [push, pull_request]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Use Node.js
+      uses: actions/setup-node@v1
+      with:
+        node-version: '14.x'
+
+    - name: Cache Node.js modules
+      uses: actions/cache@v2
+      with:
+        # npm cache files are stored in `~/.npm` on Linux/macOS
+        path: ~/.npm
+        key: ${{ runner.OS }}-node-${{ hashFiles('**/package-lock.json') }}
+        restore-keys: |
+          ${{ runner.OS }}-node-
+          ${{ runner.OS }}-
+
+    - name: Install dependencies
+      run: npm ci
+
+    - name: Lint code, run tests and create coverage report
+      run: npm run test:prod
+
+    - name: Coveralls
+      uses: coverallsapp/github-action@master
+      with:
+        github-token: ${{ secrets.GITHUB_TOKEN }}