Running rocket chat on fargate

Hi,
I have tried running rocket chat on ECS Fargate, But the mongodb container seems to be stopping with Signal15. I have attached the docker compose file and ecs-params file below.
Has anyone been able to run rocket chat on fargate?

version: '2'
services:
  rocketchat:
    image: rocket.chat
    command: bash -c 'for i in `seq 1 30`; do node main.js && s=$$? && break || s=$$?; echo "Tried $$i times. Waiting 5 secs..."; sleep 5; done; (exit $$s)'
    restart: unless-stopped
    volumes:
      - /app/uploads
    environment:
      - PORT=3000
      - ROOT_URL=https://chat.xxx.com
      - MONGO_URL=mongodb://localhost:27017/rocketchat
      - MONGO_OPLOG_URL=mongodb://localhost:27017/local
      - MAIL_URL=smtp://smtp.email
    ports:
      - 3000:3000
    labels:
      - "traefik.backend=rocketchat"
      - "traefik.frontend.rule=Host: chat.xxx.com"

  mongo:
    image: mongo:4.0
    restart: unless-stopped
    volumes:
     - /data/db
    command: mongod --smallfiles --oplogSize 128 --replSet rs0 --storageEngine=mmapv1
    labels:
      - "traefik.enable=false"

  mongo-init-replica:
    image: mongo:4.0
    command: 'bash -c "for i in `seq 1 30`; do mongo mongo/rocketchat --eval \"rs.initiate({ _id: ''rs0'', members: [ { _id: 0, host: ''localhost:27017'' } ]})\" && s=$$? && break || s=$$?; echo \"Tried $$i times. Waiting 5 secs...\"; sleep 5; done; (exit $$s)"'

ecs-params.yml

version: 1
task_definition:
  ecs_network_mode: awsvpc
  task_size:
    mem_limit: 8GB
    cpu_limit: 2048
run_params:
  network_configuration:
    awsvpc_configuration:
      assign_public_ip: ENABLED
      subnets: 
        - subnet-xxx
        - subnet-xxx