feat(docker-compose): mount local database for persistence

Added a volume to the `matrix-gptbot` service configuration in `docker-compose.yml`, mounting the local `database.db` file into the container. This change enables persistent storage for the bot's data, ensuring that data is not lost when the container is restarted or redeployed. It enhances data management and allows for more robust operation of the bot service by leveraging persistency.

This development is crucial for scenarios requiring data retention across bot updates and system maintenance activities.

docker-compose.yml

@@ -5,6 +5,7 @@ services:
     image: kumitterer/matrix-gptbot
     volumes:
       - ./config.ini:/app/config.ini
+      - ./database.db:/app/database.db
 
   pantalaimon:
     image: matrixdotorg/pantalaimon