ci: add github workflow

.github/workflows/main.yml

@@ -0,0 +1,47 @@
+name: Prophecies - CI
+
+on:
+  push:
+
+concurrency:
+  group: '${{ github.workflow }} @ ${{ github.event.pull_request.head.label || github.head_ref || github.ref }}'
+  cancel-in-progress: true
+
+jobs:
+  test-backend:
+    runs-on: ubuntu-latest
+    strategy:
+      max-parallel: 2
+      matrix:
+        python-version: ['3.9', '3.10']
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install Poetry
+        uses: snok/install-poetry@v1
+        with:
+          virtualenvs-create: true
+          virtualenvs-in-project: true
+          installer-parallel: true
+
+      - name: Load cached venv
+        id: cached-poetry-dependencies
+        uses: actions/cache@v3
+        with:
+          path: .venv
+          key: venv-${{ runner.os }}-${{ matrix.python-version }}-${{ hashFiles('**/poetry.lock') }}
+
+      - name: Install Python dependencies
+        if: steps.cached-poetry-dependencies.outputs.cache-hit != 'true'
+        run: poetry install --no-interaction --no-root 
+
+      - name: Build PLD
+        run: poetry build
+
+      - name: Run the tests with pytest
+        run: make test-back