Paste the following content:
[Unit]
Description=Gunicorn instance to serve Flask application
After=network.target
[Service]
User=www-data
Group=www-data
WorkingDirectory=/path/to/your-flask-app
Environment="PATH=/path/to/your-flask-app/venv/bin"
ExecStart=/path/to/your-flask-app/venv/bin/gunicorn --workers 3 --bind unix:/path/to/your-flask-app/developerbreeze.sock app:app
[Install]
WantedBy=multi-user.target