Help with docker-compose and existing sqlite database

[dreadedhamish]

I'm trying a very simple implementation:

1. I've left the dreamfactory db and redis settings as default.
2. Using the default sql settings for web: environment: works (removing user and hostname)
3. I've added a volume to which links to a folder where I have this database stored.
4. I can manually add Services for a) files to make this folder accessible, and b) import my databases this way.

But I can't figure out how to use this as the primary web: environment: database.

Could anyone help me out with the following settings (or send some links to example local sqlite implementations)?
for an SQLITE db /opt/dreamfactory/storage/df-localDBs/localsqlite.db with a table name TABLE1, what would the following settings need to be?

web:
environment:
SERVERNAME: dreamfactory.local
# HTTPS_HEADER: "on"
# APP_KEY: VALUE
DB_DRIVER: mysql
DB_HOST: mysql
# DB_USERNAME: df_admin
# DB_PASSWORD: df_admin
DB_DATABASE: dreamfactory

volumes:
  - df-storage:/opt/dreamfactory/storage
  - PATH/TO/localDBs:/opt/dreamfactory/storage/df-localDBs