Completely disable recursion

First of all, awesome quality image; very well done!

I was wondering how to disable recursion? The docs say it's disabled by default but it is still resolving?

> docker run --rm -ti \
> -p 5553:53/tcp \
> -p 5553:53/udp \
> -e DNS_A='test.domain=1.2.3.4' \
> -t cytopia/bind
>

`dig @127.0.0.1 -p 5553 test.domain `

> ; <<>> DiG 9.10.6 <<>> @127.0.0.1 -p 5553 test.domain
> ; (1 server found)
> ;; global options: +cmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6228
> ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 2
>
> ;; OPT PSEUDOSECTION:
> ; EDNS: version: 0, flags:; udp: 1232
> ;; QUESTION SECTION:
> ;test.domain. IN A
>
> ;; ANSWER SECTION:
> test.domain. 5 IN A 1.2.3.4

`dig @127.0.0.1 -p 5553 google.com`

> ; <<>> DiG 9.10.6 <<>> @127.0.0.1 -p 5553 google.com
> ; (1 server found)
> ;; global options: +cmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 51124
> ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
>
> ;; OPT PSEUDOSECTION:
> ; EDNS: version: 0, flags:; udp: 1232
> ;; QUESTION SECTION:
> ;google.com. IN A
>
> ;; ANSWER SECTION:
> google.com. 300 IN A 142.251.39.110