Add alembic schema check

.github/workflows/backend_check_schema.yml

@@ -0,0 +1,33 @@
+name: Check backend database schema
+on:
+  pull_request:
+    branches:
+      - main
+      - mwp_v1
+    paths:
+      - "backend/**"
+      - ".github/**"
+      - "docker/**"
+
+jobs:
+  check-schema:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Start Docker Containers
+        run: |
+          cd docker
+          ./setup-folders.sh
+          cp .env.example .env
+          chmod -R a+rwx backend_repo/ models_cache/ spacy_models/ tika/
+          python monkey_patch_docker_compose_for_backend_tests.py --disable_ray
+          export GID=$(id -g)
+          export API_PRODUCTION_WORKERS=0
+          export RAY_CONFIG="./config_test_no_gpu.yaml"
+          docker compose -f compose-test.yml up -d --quiet-pull postgres dwts-backend-api
+          echo Waiting for containers to start...
+          sleep 30
+          cd ..
+      - name: Check that database schema is up-to-date
+        run: |
+          docker exec -i demo-dwts-backend-api-1 /opt/envs/dwts/bin/alembic check