Basic Integration Test for backend

This patch implements a very basic test for commits and pull requests to
be run on GitHub Actions. This does not yet check much, but would have
caught something like the recent syntax error.

.github/.docker-compose-database.yml

@@ -0,0 +1,16 @@
+services:
+  db:
+    image: postgis/postgis:15-3.3
+    container_name: adventurelog-db
+    restart: unless-stopped
+    ports:
+      - "127.0.0.1:5432:5432"
+    environment:
+      POSTGRES_DB: database
+      POSTGRES_USER: adventure
+      POSTGRES_PASSWORD: changeme123
+    volumes:
+      - postgres_data:/var/lib/postgresql/data/
+
+volumes:
+  postgres_data:

.github/workflows/backend-test.yml

@@ -0,0 +1,61 @@
+name: Test Backend
+
+on:
+  pull_request:
+    paths:
+      - 'backend/server/**'
+      - '.github/workflows/backend-test.yml'
+  push:
+    paths:
+      - 'backend/server/**'
+      - '.github/workflows/backend-test.yml'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: set up python 3.12
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+
+      - name: install dependencies
+        run: |
+          sudo apt update -q
+          sudo apt install -y -q \
+            python3-gdal
+
+      - name: start database
+        run: |
+          docker compose -f .github/.docker-compose-database.yml up -d
+
+      - name: install python libreries
+        working-directory: backend/server
+        run: |
+          pip install -r requirements.txt
+
+      - name: run server
+        working-directory: backend/server
+        env:
+          PGHOST: "127.0.0.1"
+          PGDATABASE: "database"
+          PGUSER: "adventure"
+          PGPASSWORD: "changeme123"
+          SECRET_KEY: "changeme123"
+          DJANGO_ADMIN_USERNAME: "admin"
+          DJANGO_ADMIN_PASSWORD: "admin"
+          DJANGO_ADMIN_EMAIL: "admin@example.com"
+          PUBLIC_URL: "http://localhost:8000"
+          CSRF_TRUSTED_ORIGINS: "http://localhost:5173,http://localhost:8000"
+          DEBUG: "True"
+          FRONTEND_URL: "http://localhost:5173"
+        run: |
+          python manage.py migrate
+          python manage.py runserver &
+
+      - name: wait for backend to boot
+        run: >
+          curl -fisS --retry 60 --retry-delay 1 --retry-all-errors
+          http://localhost:8000/