🐳 Implement Docker-based testing with full CI/CD pipeline

✨ Features:
- Docker Compose testing environment (docker-compose.test.yml)
- Specialized test Dockerfile (Dockerfile.test)
- Test-specific Django settings (settings_test.py)
- Complete Drone CI/CD pipeline with 8 stages
- PostgreSQL 17 container for isolated testing
- Network isolation for testing containers

🧪 Testing improvements:
- All 6 tests passing successfully
- Fixed ServiceRequest model tests
- Added proper Category and Service imports
- Container-based testing as requested

🚀 CI/CD enhancements:
- Code quality checks (flake8, black, bandit)
- Database migration testing
- Unit and integration tests
- Docker image building and security scanning
- Telegram notifications for build status
- Production deployment pipeline
- Scheduled maintenance tasks

🔧 Dependencies:
- Added dj-database-url for DATABASE_URL parsing
- Added testing dependencies (pytest, coverage)
- Updated requirements.txt with all needed packages

🎯 Result: Complete Docker network isolated testing system ready for production CI/CD

docker-compose.test.yml

@@ -0,0 +1,55 @@
+version: '3.8'
+
+services:
+  # Тестовая база данных
+  postgres_test:
+    image: postgres:17-alpine
+    container_name: postgres_test
+    environment:
+      POSTGRES_DB: smartsoltech_test
+      POSTGRES_USER: postgres
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_HOST_AUTH_METHOD: trust
+    ports:
+      - "5433:5432"
+    networks:
+      - test_network
+    volumes:
+      - test_pgdata:/var/lib/postgresql/data
+
+  # Тестовое Django приложение
+  django_test:
+    build:
+      context: .
+      dockerfile: Dockerfile.test
+    container_name: django_test
+    environment:
+      DATABASE_URL: postgresql://postgres:postgres@postgres_test:5432/smartsoltech_test
+      SECRET_KEY: test-secret-key-for-ci-very-long-and-secure-key-12345
+      DEBUG: "False"
+      ALLOWED_HOSTS: localhost,127.0.0.1,postgres_test,*
+      DJANGO_SETTINGS_MODULE: smartsoltech.settings_test
+      TELEGRAM_BOT_TOKEN: test-token-for-ci
+    depends_on:
+      - postgres_test
+    networks:
+      - test_network
+    command: >
+      sh -c "
+        echo 'Ожидание готовности PostgreSQL...' &&
+        until pg_isready -h postgres_test -p 5432 -U postgres; do 
+          echo 'Waiting for postgres_test...' && sleep 2; 
+        done &&
+        echo 'Запуск миграций...' &&
+        cd smartsoltech &&
+        python manage.py migrate --settings=smartsoltech.settings_test &&
+        echo 'Запуск тестов...' &&
+        python manage.py test --settings=smartsoltech.settings_test --verbosity=2
+      "
+
+volumes:
+  test_pgdata:
+
+networks:
+  test_network:
+    driver: bridge