disable introspection when environment is set to production

src/index.ts

@@ -12,7 +12,8 @@ const typeDefs = readFileSync("./schema.graphqls", "utf8");
 async function main() {
   const server = new ApolloServer<ServerContext>({
     typeDefs,
-    resolvers
+    resolvers,
+    introspection: process.env.NODE_ENV !== "production",
   });
 
   const repository = new UnoptimizedInMemoryRepository();