Add step to add `apollo.config.js`

Have had a few intercom users saying they ran `npx apollo service:check && npx apollo service:push` and got `Error: No service found to link to Engine`

The tutorial page doesn't currently mention anything about configs

https://www.apollographql.com/docs/tutorial/production.html

There are docs for service settings from the apollo-tooling readme that can be used as reference - https://github.com/apollographql/apollo-tooling#service-settings

Related: https://github.com/apollographql/apollo-tooling/issues/771

从 issue 中链接的 production tutorial 页面开始，将其中关于 service 设置的指导与 apollo-tooling README 中的参考内容进行比较。更新教程，说明在执行 service:check 和 service:push 命令之前所需的 apollo.config.js 配置，然后验证文档化的流程能够解决报告的错误。

由索引模型根据 Issue 内容生成。