Add a placeholder implementation of ParkingStructureResolvers

src/resolvers/ParkingStructureResolvers.ts

@@ -0,0 +1,10 @@
+import { Resolvers } from "../generated/graphql";
+import { ServerContext } from "../ServerContext";
+
+export const ParkingStructureResolvers: Resolvers<ServerContext> = {
+  ParkingStructure: {
+    historicalAverages: async (parent, args, contextValue, _info) => {
+      return [];
+    }
+  }
+}