Add rasa core service on RasaX


how can I add rasa core service on the docker container for rasa x ?

You mean in addition to the existing rasa-production and rasa-worker service? Rasa X CE currently does not support multiple environments (e.g. a rasa-development instance).

Also, you wrote rasa core service, but Rasa X only works with rasa (rasa core and rasa nlu were merged in rasa nlu).