🐳 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

Dockerfile.test

@@ -0,0 +1,30 @@
+# Dockerfile для тестирования
+FROM python:3.10-slim
+
+# Установка системных зависимостей
+RUN apt-get update && apt-get install -y \
+    libpq-dev \
+    gcc \
+    curl \
+    postgresql-client \
+    && rm -rf /var/lib/apt/lists/*
+
+# Рабочая директория
+WORKDIR /app
+
+# Копируем requirements и устанавливаем зависимости
+COPY requirements.txt .
+RUN pip install --upgrade pip && pip install -r requirements.txt
+
+# Копируем код приложения
+COPY . .
+
+# Настройки для тестов
+ENV PYTHONPATH=/app
+ENV DJANGO_SETTINGS_MODULE=smartsoltech.settings_test
+ENV SECRET_KEY=test-secret-key-for-ci-very-long-and-secure-key-12345
+ENV DEBUG=False
+ENV ALLOWED_HOSTS=localhost,127.0.0.1,postgres,*
+
+# Команда по умолчанию
+CMD ["python", "smartsoltech/manage.py", "test", "--settings=smartsoltech.settings_test", "--verbosity=2"]