Add GraphqlService to handle GraphQL requests

src/graphql/graphql.module.ts

@@ -0,0 +1,8 @@
+import { Module } from '@nestjs/common';
+import { GraphqlService } from './graphql.service';
+import { GraphqlResolver } from './graphql.resolver';
+
+@Module({
+  providers: [GraphqlService, GraphqlResolver],
+})
+export class GraphqlModule {}