Well if you're willing to give it another shot, this is the docker-compose I use with it. I also have ruTorrent running because that's what I was using before I heard about flood and just never bothered to strip it from the setup.

---
version: "3.4"

services:
  # rTorrent/ruTorrent stuffs
  geoip-updater:
    image: crazymax/geoip-updater:latest
    container_name: geoip
    volumes:
      - "/opt/rtorrent/data/geoip:/data"
    environment:
      - LICENSE_KEY={{ geoip_maxmind }}
      - TZ=America/Chicago
      - EDITION_IDS=GeoLite2-City,GeoLite2-Country
      - DOWNLOAD_PATH=/data
      - SCHEDULE=0 0 * * 0
      - LOG_LEVEL=info
      - LOG_JSON=false
    restart: unless-stopped

  rutorrent:
    image: crazymax/rtorrent-rutorrent:latest
    container_name: rutorrent
    ports:
      - 4200:8080
      - 51999:51999
    env_file:
      - "rtorrent-rutorrent.env"
    volumes:
      - "/opt/rtorrent/data:/data"
      - "/mnt/torrents:/downloads"
      - "/opt/rtorrent/passwd:/passwd"
      - "/opt/rtorrent/sock:/run/rtorrent"
    ulimits:
      nproc: 65535
      nofile:
        soft: 32000
        hard: 40000
    restart: unless-stopped

  rtorrent-logs:
    image: bash
    container_name: rtorrent-logs
    command: bash -c 'tail -f /log/*.log'
    depends_on:
      - rutorrent
    volumes:
      - "/opt/rtorrent/data/rtorrent/log:/log"
    restart: unless-stopped

  flood:
    image: jesec/flood
    container_name: flood
    user: 1000:1000
    command: --port 3001 --allowedpath /downloads
    ports:
      - 3001:3001
    environment:
      HOME: /config
    depends_on:
      - rutorrent
    volumes:
      - "/opt/rtorrent/flood:/config"
      - "/mnt/torrents:/downloads"
      - "/opt/rtorrent/sock:/rtorrent-sock"
    restart: unless-stopped

And here is the rtorrent-rutorrent.env file:

TZ=America/Los_Angeles
PUID=1000
PGID=1000

RT_INC_PORT=51999

MEMORY_LIMIT=8192M
UPLOAD_MAX_SIZE=16M
OPCACHE_MEM_SIZE=512
MAX_FILE_UPLOADS=50
REAL_IP_FROM=0.0.0.0/32
REAL_IP_HEADER=X-Forwarded-For
LOG_IP_VAR=remote_addr

XMLRPC_AUTHBASIC_STRING=rTorrent XMLRPC restricted access
RUTORRENT_AUTHBASIC_STRING=ruTorrent restricted access
WEBDAV_AUTHBASIC_STRING=WebDAV restricted access

RT_LOG_LEVEL=info
RT_LOG_EXECUTE=false
RT_LOG_XMLRPC=false

RU_REMOVE_CORE_PLUGINS=
RU_HTTP_USER_AGENT=Mozilla/5.0 (Windows NT 6.0; WOW64; rv:12.0) Gecko/20100101 Firefox/12.0
RU_HTTP_TIME_OUT=30
RU_HTTP_USE_GZIP=true
RU_RPC_TIME_OUT=5
RU_LOG_RPC_CALLS=false
RU_LOG_RPC_FAULTS=true
RU_PHP_USE_GZIP=false
RU_PHP_GZIP_LEVEL=2
RU_SCHEDULE_RAND=10
RU_LOG_FILE=/data/rutorrent/rutorrent.log
RU_DO_DIAGNOSTIC=true
RU_SAVE_UPLOADED_TORRENTS=true
RU_OVERWRITE_UPLOADED_TORRENTS=false
RU_FORBID_USER_SETTINGS=false
RU_LOCALE=UTF8

I think the only other thing to mention is you'll need to register for a maxmind API key and drop that into the environment variable field.