CI: add automated tests workflow

.github/workflows/rubyonrails.yml

@@ -0,0 +1,36 @@
+# This workflow uses actions that are not certified by GitHub.  They are
+# provided by a third-party and are governed by separate terms of service,
+# privacy policy, and support documentation.
+#
+# This workflow will install a prebuilt Ruby version, install dependencies, and
+# run tests and linters.
+name: "Ruby on Rails CI"
+on:
+  push:
+    branches: ["main"]
+  pull_request:
+    branches: ["main"]
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: Install Ruby and gems
+        uses: ruby/setup-ruby@v1.157.0
+        with:
+          ruby-version: '3.2.2'
+          bundler-cache: true
+
+      - name: Install dependencies
+        run: bundle install
+        working-directory: ./backend
+
+      - name: Set up database schema
+        run: bundle exec rails db:schema:load
+        working-directory: ./backend
+
+      - name: Run tests
+        run: bundle exec rspec
+        working-directory: ./backend