Create a rule that adds elements to a list.

For example, the rule

Install.Rule.rule
    [ Install.ElementToList.config
        "User"
        "userTypes"
        [ "Admin", "SystemAdmin" ]
        |> Install.Rule.elementToList
    ]

results in the following fix for function User.userTypes:

[ Standard ] -> [ Standard, Admin, SystemAdmin ]

Configuration for rule.