class ViewModel::Migrator

def initialize(required_versions)
  @paths = required_versions.each_with_object({}) do |(viewmodel_class, required_version), h|
    if required_version != viewmodel_class.schema_version
      path = viewmodel_class.migration_path(from: required_version, to: viewmodel_class.schema_version)
      h[viewmodel_class.view_name] = path
    end
  end
  @versions = required_versions.each_with_object({}) do |(viewmodel_class, required_version), h|
    h[viewmodel_class.view_name] = [required_version, viewmodel_class.schema_version]
  end
end