Price history and trends retrieval

[pstoica]

You can see the endpoints in app.js, and you should be able to query by a start date (or an active date for the whole US; actually, since the timeline may step day-by-day, we shouldn't make a request every time; look into storing all the map data on the client in the beginning, or loading a month at a time?).

Writing all this on the fly, sorry.

[pstoica]

@vi-s as said in #2, we don't need filtering by date ranges now (aside from looking at a specific month).

[vis-123]

kk, so we're filtering trends data solely by location now?

[pstoica]

yerp.