Same USER as the host that can read/write to ~/.

So I am trying to build a container that has [chezmoi](https://www.chezmoi.io) and [Vault](https://www.vaultproject.io) in it. I need my `$USER` to be the same and `$HOSTNAME` in the container and have read/write access to my home directory. Chezmoi reads [templates](https://www.chezmoi.io/docs/reference/#template-variables) that specify both the hostname and user for template logic.

I started with: [Running Docker Containers as Current Host User](https://jtreminio.com/blog/running-docker-containers-as-current-host-user/), but found that if I had the UID 1000:1000 in the container this wasn't mapped in my container. Perhaps I need to set this to a different UID? My subuid/subgid is:

#### /etc/subuid:
```
daniel:100000:65536
```
#### /etc/subgid:
```
daniel:100000:65536
```

I then found [User IDs and (rootless) containers with Podman](https://blog.christophersmart.com/2021/01/26/user-ids-and-rootless-containers-with-podman/), but it seems that `--user` has to be set with `podman run`. [Should you use the --user flag in rootless containers?](https://www.redhat.com/sysadmin/user-flag-rootless-containers), mentioned `--userns=keep-id` but I'd like to keep it in my compose file if possible. Apparently that can't be specified https://github.com/containers/podman-compose/issues/166, one solution there mentions specifying this in .bashrc/.zshrc, but I'd really rather use a local `.env` file in my docker-compose directory.

I'm not really sure if those features are what I need to solve this, so any advice would be welcome. This is what I have so far:

#### .env:
```bash
COMPOSE_PROJECT_NAME=chezmoi
COMPOSE_HTTP_TIMEOUT=300
COMPOSE_FILE=chezmoi-compose.yml
USER_ID=0
GROUP_ID=0
PODMAN_USERNS=keep-id
```

#### chezmoi-compose.yml:
```yaml
services:
chezmoi:
container_name: chezmoi
hostname: ${HOSTNAME}
build:
context: .
dockerfile: ./chezmoi/Dockerfile
security_opt:
label: disable
args:
USER_ID: ${USER_ID:-0}
GROUP_ID: ${GROUP_ID:-0}
USER: ${USER:-0}
volumes:
- ${HOME}:/home/${USER}
```

#### chezmoi/Dockerfile:
```Dockerfile
FROM fedora

ARG USER_ID
ARG GROUP_ID
ARG USER

RUN latestChezmoi=$(curl -s https://api.github.com/repos/twpayne/chezmoi/releases/latest | grep -P '^(?=.*browser_download_url.*rpm)(?=.*x86_64)' | cut -d '"' -f 4) && dnf -y install $latestChezmoi

RUN dnf install -y dnf-plugins-core; dnf config-manager --add-repo https://rpm.releases.hashicorp.com/fedora/hashicorp.repo; dnf -y install vault

RUN if [ ${USER_ID:-0} -ne 0 ] && [ ${GROUP_ID:-0} -ne 0 ]; then \
groupadd -g ${GROUP_ID} ${USER} &&\
useradd -l -u ${USER_ID} -g ${USER} ${USER} &&\
install -Z -d -m 0755 -o ${USER} -g ${USER} /home/${USER} ;fi

USER $USER
WORKDIR $USER
ENTRYPOINT ["tail", "-f", "/dev/null"]
```

I compiled this with (Incidentally I ran into https://github.com/containers/podman-compose/issues/371) :smile:

```
podman-compose -f chezmoi-compose.yml up
```

I used this to get a shell:
```
podman container exec -it chezmoi bash
```

**Output:**
```
$ podman-compose version
['podman', '--version', '']
using podman version: 3.4.4
podman-composer version 0.1.8
podman --version
podman version 3.4.4
exit code: 0
```

**Environment:** Fedora Silverblue 35

```
podman version
Version: 3.4.4
API Version: 3.4.4
Go Version: go1.16.8
Built: Thu Dec 9 08:15:07 2021
OS/Arch: linux/amd64
```

**Additional context**

Also something else would be nice if there was a `support` label. I think this would be useful as some people have asked questions and they weren't really bugs or new features.