Based on arm32v6/alpine:latest which make it compatible with Raspberry Pi Zero (||w) This image use php7-fpm with nginx instead of apache2 in official image

docker run -d --name fireflyiii \
-p 80:80 \
-e APP_KEY=SomeRandomStringOf32CharsExactly \
-e DB_HOST=CHANGEME \
-e DB_DATABASE=fireflyiii \
-e DB_USERNAME=fireflyiii \
-e DB_PASSWORD=CHANGEME \
-e DB_CONNECTION=mysql \
-e DB_PORT=3306 \
-it threadrr/firefly-iii-arm32v6-raspberry-pi:latest

Firefly-iii Official repository: https://github.com/firefly-iii/firefly-iii