Extend GitHub Actions to install node and yarn

.github/workflows/retrospring.yml

@@ -46,6 +46,10 @@ jobs:
         uses: actions/setup-ruby@v1
         with:
           ruby-version: 2.7.x
+      - name: Set up Node 12
+        uses: actions/setup-node@v1
+        with:
+          node-version: '12'
       - name: Install dependencies
         run: sudo apt update && sudo apt-get install -y libpq-dev libxml2-dev libxslt1-dev libmagickwand-dev imagemagick
       - name: Copy default configuration
@@ -58,6 +62,10 @@ jobs:
           bundle config path vendor/bundle
           bundle config set without 'production'
           bundle install --jobs 4 --retry 3
+      - name: Install node modules
+        run: |
+          npm i -g yarn
+          yarn install
       - name: Set up database
         run: bundle exec rake db:setup
         env: