def env(name, value)
      ENV[name] = value

      if value
        Stairs.configuration.env_adapter.set name, value
      else
        Stairs.configuration.env_adapter.unset name
      end
    end
def env(name, value)
      ENV[name] = value

      if value
        Stairs.configuration.env_adapter.set name, value
      else
        Stairs.configuration.env_adapter.unset name
      end
    end
Set or update env var