ci: add github workflow to build flake and run tests

.github/workflows/build-flake.yml

@@ -0,0 +1,19 @@
+name: Build Nix Flake
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  build-flake:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - uses: cachix/install-nix-action@v15
+
+      - run: nix build

.github/workflows/run-tests.yml

@@ -0,0 +1,39 @@
+name: Run tests
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  run-tests:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+
+    - name: Set up Python 3.10
+      uses: actions/setup-python@v3
+      with:
+        python-version: "3.10"
+
+    - uses: snok/install-poetry@v1
+      with:
+        version: 1.3.0
+        virtualenvs-create: true
+
+    - name: Install dependencies
+      run: |
+        poetry -C fifoci/runner install --no-interaction --no-root
+        poetry -C fifoci/frontend install --no-interaction --no-root
+
+    - name: Check runner coding style
+      run: poetry run -C fifoci/runner black --check fifoci/runner
+
+    - name: Check frontend coding style
+      run: poetry run -C fifoci/frontend black --check fifoci/frontend
+
+    - name: Run frontend unit tests
+      run: poetry run -C fifoci/frontend fifoci-frontend-manage test --noinput