BookStack + openLDAP => How do I get BookStack roles to load from LDAP Groups?

Question

I need some help please in getting BookStack and OpenLDAP to work to automatically map LDAP groups to BookStack Roles.

I have the BookStack authentication via LDAP working but all users seem to only have Viewer permissions.

I'm using this BookStack docker image: https://github.com/solidnerd/docker-bookstack

And this OpenLDAP docker image: https://github.com/osixia/docker-openldap

For anyone who has got the LDAP groups -> BookStack roles working, would you please offer some advice?

I have read conflicting opinions about the need to add a memberOf overlay when using openLDAP. Some articles say that I need to add it, but I don't seem to have config permissions (or I don't know how to access the LDAP server correctly with the docker image). I also saw this closed issue in the osixia/docker-openldap that made is seem that memberOf should work if I setup the LDAP entries correctly: https://github.com/osixia/docker-openldap/issues/258

From what I can tell, it seems that if memberOf is working, if I have an LDAP group named "Docs Admin", the users that are a member of that group should get automatically loaded with the role of Admin. Is there a list somewhere of the LDAP Group -> BookStack Roles? What is the LDAP group that a user needs to be a member of to get the Role of BookStack Admin?

Does anyone have any details regarding the exact LDAP structures that I need to create to get this to work?

Do I need to install some sort of memberOf overlay when using the osixia/docker-openldap image? Does anyone have the specific steps (I've tried a number of different examples on the host machine that is hosting the docker containers and they fail with "ldap_modify: Insufficient access (50)" (e.g. https://devopsideas.com/planning-of-ldap-dit-structure-and-config-of-overlays-access-ppolicy/ or https://www.adimian.com/blog/2014/10/how-to-enable-memberof-using-openldap/ )

Here's my BookStack docker-compose.yml:

version: '2'
services:
  mysql:
    image: mysql:5.7.21
    environment:
    - MYSQL_ROOT_PASSWORD=secret
    - MYSQL_DATABASE=bookstack
    - MYSQL_USER=bookstack
    - MYSQL_PASSWORD=secret
    volumes:
    - mysql-data:/var/lib/mysql

  bookstack:
    image: solidnerd/bookstack:0.25.2
    depends_on:
    - mysql
    environment:
    - APP_DEBUG=true
    - DB_HOST=mysql:3306
    - DB_DATABASE=bookstack
    - DB_USERNAME=bookstack
    - DB_PASSWORD=secret
    - AUTH_METHOD=ldap
    - LDAP_SERVER=ldap://192.168.0.2:389
    - LDAP_BASE_DN=dc=example,dc=com
    - LDAP_DN=cn=admin,dc=example,dc=com
    - LDAP_PASS=admin
    - LDAP_USER_FILTER=(&(uid=$${user}))
    - LDAP_EMAIL_ATTRIBUTE=mail
    - LDAP_VERSION=3
    - LDAP_USER_TO_GROUPS=true
    - LDAP_GROUP_ATTRIBUTE="memberOf"
    - LDAP_REMOVE_FROM_GROUPS=false
    volumes:
    - uploads:/var/www/bookstack/public/uploads
    - storage-uploads:/var/www/bookstack/public/storage
    ports:
    - "8080:80"

volumes:
 mysql-data:
 uploads:
 storage-uploads: