Looking for clarity on setting up couchdb single_node with docker-compose

## Expected Behavior

I am trying to set up a single node instance of **couchdb:2** using docker-compose. I understand from reading the README the limitation that the `_users`, `_replicator` and `global_changes` dbs need to be set up after installation. I tried adding the `single_node=true` config in a `local.ini` file and copying that to `/opt/couchdb/etc/` and `/opt/couchdb/etc/local.d` in via Dockerfile. Neither of those approaches seem to work. According to this [comment](https://github.com/apache/couchdb/discussions/2948#discussioncomment-29228), this seems to be a valid approach.

Is it not a viable solution for **couchdb:2**?

FWIW: Here is the `local.ini` file from inside the container:
```
root@528ea27a75a7:/opt/couchdb/etc/# cat local.ini
[couchdb]
single_node = true

[chttpd]
bind_address = any

[httpd]
bind_address = any

[couch_httpd_auth]
require_valid_user = true

[chttpd]
require_valid_user = true
```

If not, then I need to create the `_users`, `_replicator` and `_global_changes` dbs a different way. I see [this comment](https://github.com/apache/couchdb-docker/issues/54#issuecomment-520153526) in the same thread. Is this still the best approach?

Much appreciated.