init Github Actions for CI

.github/workflows/backend-app.yml

@@ -0,0 +1,31 @@
+name: Backend Python application
+
+on: [push]
+
+defaults:
+  run:
+    working-directory: backend
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.11"]
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade -r requirements/dev.txt
+
+      - name: Test with pytest
+        run: |
+          pytest