How to start a specific Ruby version in Visual Studio Code

I have rbenv installed and changed my Ruby version with:

rbenv shell 2.6.0

I installed the Ruby extension in Visual Studio Code.

I want to start Rails with that version. My configuration looks like:

    "version": "0.2.0",
    "configurations": [

    {
        "name": "Rails server",
        "type": "Ruby",
        "request": "launch",
        "program": "${workspaceRoot}/bin/rails",
        "args": [
            "server"
        ]
    }
]

}

Rails still starts with my standard Ruby v2.7