I'm trying to run PHP built in web server as startup for my container, but docker-compose up complain that it failed to parse the ` symbol (backquote? backtick?) in my docker-compose.yml 

Here's my docker-compose.yml

```
version: "3"
services:
  sf-api:
    image: reston/php:7.1
    ports: 
      - "8000:8000"
    volumes:
      - ".:/tmp/target"
    working_dir: "/tmp/target"
    command: ["php","-S","`hostname -i`:8000"]   

```

What I'm trying to do is to make the web server binds to container external IP instead of 127.0.0.1.

Edit:
Here's the output running docker-compose up

```
$ docker-compose up
Recreating storefrontapi_sf-api_1 ...
Recreating storefrontapi_sf-api_1 ... done
Attaching to storefrontapi_sf-api_1
sf-api_1  | Invalid address: `hostname -i`
storefrontapi_sf-api_1 exited with code 1

```