PS C:\Users\ICO-RAFAEL\Desktop\alura-docker-cap06\alura-docker-cap06> docker-compose build
ERROR: The Compose file '.\docker-compose.yml' is invalid because:
services.node1.build.context contains null, which is an invalid type, it should be a string
services.node2.build.context contains null, which is an invalid type, it should be a string
services.node3.build.context contains null, which is an invalid type, it should be a string
services.nginx.build.context contains null, which is an invalid type, it should be a string
