I am having troubles understanding the following DevOps concept.
I have developed a dockerized web app using docker-compose. It is in my local and I can upload it to any cloud service I want and it works fine. The point is that when I try to establish a CI/CD pipeline, specifically CircleCI (I don't know how it works with any other alternative), I found out that I need to use a yml file that specifies a docker image for a given job.
My question is: does this mean that my entire web app will run in this specific image? If so, how can I translate my current working web app that uses docker-compose to a web app that takes advantage of CI/CD?