update graphql schema

schema.graphqls

@@ -1,4 +1,3 @@
-# Base types
 type System {
   id: ID!
   name: String!
@@ -8,6 +7,19 @@ type System {
   stop(id: ID): Stop
   shuttles: [Shuttle!]
   shuttle(id: ID): Shuttle
+
+  # TODO: Implement these in system resolvers
+  parkingStructures: [ParkingStructure!]
+  parkingStructure(id: ID): ParkingStructure!
+}
+
+type ParkingStructure {
+  id: ID!
+  name: String!
+  capacity: Int!
+  spotsAvailable: Int!
+  coordinates: Coordinates!
+  address: String!
 }
 
 type Route {