### Description
There is no docker compose file version 3.9, see
https://docs.docker.com/compose/compose-file/compose-versioning/. The
`init` command is used in the compose file and I wonder if we can set
this to 3.7. When I followed the docs here
https://libretime.org/docs/admin-manual/install/install-using-docker/, I
was unable to get the docker compose to work because of a version issue.
So I upgraded docker (on Ubuntu focal) but realised that 3.9 isn't even
mentioned on the Docker website. 3.8 is, which I tried to use but it
failed. 3.7 worked for me.
**I have updated the documentation to reflect these changes**:
Docs are not affected.
### Testing Notes
**What I did:**
I was following the
[docs](https://libretime.org/docs/admin-manual/install/install-using-docker/)
but then rand into a docker compose file version error. I'm using docker
engine version 26,
```
Client: Docker Engine - Community
Version: 26.0.0
API version: 1.45
Go version: go1.21.8
Git commit: 2ae903e
Built: Wed Mar 20 15:17:51 2024
OS/Arch: linux/amd64
Context: default
Server: Docker Engine - Community
Engine:
Version: 26.0.0
API version: 1.45 (minimum version 1.24)
Go version: go1.21.8
Git commit: 8b79278
Built: Wed Mar 20 15:17:51 2024
OS/Arch: linux/amd64
Experimental: false
containerd:
Version: 1.6.28
GitCommit: ae07eda36dd25f8a1b98dfbf587313b99c0190bb
runc:
Version: 1.1.12
GitCommit: v1.1.12-0-g51d5e94
docker-init:
Version: 0.19.0
GitCommit: de40ad0
Ubuntu Version
Distributor ID: Ubuntu
Description: Ubuntu 20.04.6 LTS
Release: 20.04
Codename: focal
```
which is very recent. When I checked the docker compose version
[page](https://docs.docker.com/compose/compose-file/compose-versioning/),
it doesn't even list 3.9 as a version, only 3.8. For whatever reason 3.8
did not work for me, but 3.7 does.
**How you can replicate my testing:**
Follow the docs,
https://libretime.org/docs/admin-manual/install/install-using-docker/.
If docker compose fails to run, and says
```
ERROR: Version in "./docker-compose.yml" is unsupported. You might be seeing this error because you're using the wrong Compose file version. Either specify a supported version (e.g "2.2" or "3.3") and place your service definitions under the `services` key, or omit the `version` key and place your service definitions at the root of the file to use version 1.
```
then change the version to 3.7.
### **Links**
N/A
Jonas L
Keoni Mahelona
jo
Kyle Robbertze