How to configure docker-compose.yml to up a container as root

I'm trying to connect two containers with a docker-compose-yml, but it isn't working. This is my docker-compose.yml file:

version: "3"
services:
    datapower:
        build: .
        ports:
            - "9090:9090"
        depends_on:
            - db
    db:
        image: "microsoft/mssql-server-linux:2017-latest"
        environment:
            SA_PASSWORD: "your_password"
            ACCEPT_EULA: "Y"
        ports:
        - "1433:1433"

When I make:

docker-compose up

This up my two containers. Then I stop one container and then I run the same container stoped independiently like:

docker-compose run -u root --name nameofcontainer 'name of container named in docker-compose.yml'

With this, the connection of the containers works. Exists a method to configure my docker-compose.yml to connect my containers like root without stop a container and run independently?

Update:

There exists the user property that can be set in the compose file. This is documented in docker-compose file reference.

...
services:
    datapower:
        build: .
        user: root
        ports:
            - "9090:9090"
        depends_on:
            - db
...