3.x video notes

Things I maybe should have mentioned to note for the future:

* I don't need to split latitude and longitude string since it stays as comma-delimited for both dark sky and openAQ!
* I should have been more specific once I start using URL query string with openAQ and tied that back to how I'm doing the GET request with URL parameters in my node server.

No file, test, or concrete code change is named in this note. Start by reviewing the video material and the Node server examples involving OpenAQ, URL query strings, and GET parameters; done requires an agreed scope for updating those explanations.

索引モデルが issue の本文から書いたものです。