Issues with mounting $(pwd)/Caddyfile

Hi, I'm currently having trouble with mounting the Caddyfile into the container:

```sh
jannik@cheesegrater:/tmp/caddy$ ls
Caddyfile index.html
jannik@cheesegrater:/tmp/caddy$ stat Caddyfile
File: Caddyfile
Size: 21 Blocks: 0 IO Block: 512 regular file
Device: 2h/2d Inode: 3096224744076277 Links: 1
Access: (0666/-rw-rw-rw-) Uid: ( 1000/ jannik) Gid: ( 1000/ jannik)
Access: 2018-10-24 21:52:53.310144100 +0200
Modify: 2018-10-24 21:52:53.311139600 +0200
Change: 2018-10-24 21:52:53.311139600 +0200
Birth: -
jannik@cheesegrater:/tmp/caddy$ cat Caddyfile
https://cheesegrater
jannik@cheesegrater:/tmp/caddy$ docker run -it \
> -v $(pwd)/Caddyfile:/etc/Caddyfile \
> -p 80:80 -p 443:443 abiosoft/caddy
docker: Error response from daemon: OCI runtime create failed: container_linux.go:348: starting container process caused "process_linux.go:402: container init caused \"rootfs_linux.go:58: mounting \\\"/tmp/caddy/Caddyfile\\\" to rootfs \\\"/var/lib/docker/overlay2/bb(...)5f/merged\\\" at \\\"/var/lib/docker/overlay2/bb(...)95f/merged/etc/Caddyfile\\\" caused \\\"not a directory\\\"\"": unknown: Are you trying to mount a directory onto a file (or vice-versa)? Check if the specified host path exists and is the expected type.
```

Do you have any idea what might help in such a case? I'm using abiosoft/caddy in a larger production env, but this small environment does not want to work. 😞