I disagree with running RVM in a docker container. The point of RVM is to manage multiple versions of ruby and a container is only meant to have a single responsibility so running multiple versions of ruby is not advised.
I think you're better off installing the required version with Ruby Install [1] rather than adding the complexity of a version manager.
I think you're better off installing the required version with Ruby Install [1] rather than adding the complexity of a version manager.
[1] - https://github.com/postmodern/ruby-install#readme