def distance_to_nearby(id)
      unless self.nearby_station_ids.include?(id.to_i)
        raise "Station #{id} is not a nearby station"
      end

      sta = self.nearby_stations.find { |s| s['id'].to_i == id.to_i }
      sta['distance']
    end
def distance_to_nearby(id)
      unless self.nearby_station_ids.include?(id.to_i)
        raise "Station #{id} is not a nearby station"
      end

      sta = self.nearby_stations.find { |s| s['id'].to_i == id.to_i }
      sta['distance']
    end
Returns the distance to a nearby station (in miles?)
 @param  id [Integer] [Id of a nearby station]

 @return [Float] [Distance to nearby station in miles]