def symbolise(data)
      return {} unless data
      # Symbolize keys.
      Hash[data.map { |k, v| [k.to_sym, v] }]
    end
def symbolise(data)
      return {} unless data
      # Symbolize keys.
      Hash[data.map { |k, v| [k.to_sym, v] }]
    end
Symbolizes keys. Changes `database` key to `database_dir`.