Here is my docker-compose.yml file: 

```
version:'2':  
services: 
    redis:
        image: redis  
        environment: 
            - HOST='localhost'
            - PORT=6379
        ports: 
            -"0.0.0.0:${PORT}:6379"

```

I get this error on running docker-compose up:

```
ERROR: The Compose file './docker-compose.yml' is invalid because:
Invalid service name 'services' - only [a-zA-Z0-9\._\-] characters are allowed
Unsupported config option for services: 'redis'

```