querying `launches` returns errors on "final" repo.

从 final/server 教程实现开始，检查 playground 中 GetLaunches 查询所使用的 schema。将查询请求的字段与 LaunchConnection 类型和教程文本进行比较。当文档中的查询与最终 schema 匹配，并且运行时没有 GraphQL 验证错误时，即表示完成。

It seems the tutorial is out of date, as even the final returns errors, so I know it isn't with my implementation after going through the tutorial.

The playground returns the following after running the GetLaunches query from the tutorial:

{
  "error": {
    "errors": [
      {
        "message": "Cannot query field \"id\" on type \"LaunchConnection\".",
        "locations": [
          {
            "line": 3,
            "column": 5
          }
        ],
        "extensions": {
          "code": "GRAPHQL_VALIDATION_FAILED",
          "exception": {
            "stacktrace": [
              "GraphQLError: Cannot query field \"id\" on type \"LaunchConnection\".",
              "    at Object.Field (/home/petty/Github/apollo-graphql/fullstack-tutorial/final/server/node_modules/graphql/validation/rules/FieldsOnCorrectType.js:64:31)",
              "    at Object.enter (/home/petty/Github/apollo-graphql/fullstack-tutorial/final/server/node_modules/graphql/language/visitor.js:333:29)",
              "    at Object.enter (/home/petty/Github/apollo-graphql/fullstack-tutorial/final/server/node_modules/graphql/language/visitor.js:384:25)",
              "    at visit (/home/petty/Github/apollo-graphql/fullstack-tutorial/final/server/node_modules/graphql/language/visitor.js:251:26)",
              "    at Object.validate (/home/petty/Github/apollo-graphql/fullstack-tutorial/final/server/node_modules/graphql/validation/validate.js:63:22)",
              "    at validate (/home/petty/Github/apollo-graphql/fullstack-tutorial/final/server/node_modules/apollo-server-core/dist/requestPipeline.js:172:32)",
              "    at Object.<anonymous> (/home/petty/Github/apollo-graphql/fullstack-tutorial/final/server/node_modules/apollo-server-core/dist/requestPipeline.js:113:38)",
              "    at Generator.next (<anonymous>)",
              "    at fulfilled (/home/petty/Github/apollo-graphql/fullstack-tutorial/final/server/node_modules/apollo-server-core/dist/requestPipeline.js:4:58)",
              "    at process._tickCallback (internal/process/next_tick.js:68:7)"
            ]
          }
        }
      },
      {
        "message": "Cannot query field \"mission\" on type \"LaunchConnection\".",
        "locations": [
          {
            "line": 4,
            "column": 5
          }
        ],
        "extensions": {
          "code": "GRAPHQL_VALIDATION_FAILED",
          "exception": {
            "stacktrace": [
              "GraphQLError: Cannot query field \"mission\" on type \"LaunchConnection\".",
              "    at Object.Field (/home/petty/Github/apollo-graphql/fullstack-tutorial/final/server/node_modules/graphql/validation/rules/FieldsOnCorrectType.js:64:31)",
              "    at Object.enter (/home/petty/Github/apollo-graphql/fullstack-tutorial/final/server/node_modules/graphql/language/visitor.js:333:29)",
              "    at Object.enter (/home/petty/Github/apollo-graphql/fullstack-tutorial/final/server/node_modules/graphql/language/visitor.js:384:25)",
              "    at visit (/home/petty/Github/apollo-graphql/fullstack-tutorial/final/server/node_modules/graphql/language/visitor.js:251:26)",
              "    at Object.validate (/home/petty/Github/apollo-graphql/fullstack-tutorial/final/server/node_modules/graphql/validation/validate.js:63:22)",
              "    at validate (/home/petty/Github/apollo-graphql/fullstack-tutorial/final/server/node_modules/apollo-server-core/dist/requestPipeline.js:172:32)",
              "    at Object.<anonymous> (/home/petty/Github/apollo-graphql/fullstack-tutorial/final/server/node_modules/apollo-server-core/dist/requestPipeline.js:113:38)",
              "    at Generator.next (<anonymous>)",
              "    at fulfilled (/home/petty/Github/apollo-graphql/fullstack-tutorial/final/server/node_modules/apollo-server-core/dist/requestPipeline.js:4:58)",
              "    at process._tickCallback (internal/process/next_tick.js:68:7)"
            ]
          }
        }
      }
    ]
  }
}