add heatmap, maybe on homepage about sf-ballot-measures

[nrjones8]

some really good examples of Nivo here: https://nivo.rocks/storybook/?path=/story/heatmap--default

[nrjones8]

maybe apexcharts won't work, need a custom tooltip and doesn't seem possible with it...apexcharts/apexcharts.js#52 (comment)

[nrjones8]

other options:

1. http://uber.github.io/react-vis/documentation/series-reference/heatmap-series (and https://github.com/uber/react-vis/blob/master/showcase/plot/labeled-heatmap.js)
2. https://www.npmjs.com/package/react-heatmap-grid (simple, only a heatmap tho)
3. Nivo seems pretty nifty: https://nivo.rocks/heatmap/ - but looks way more complicated than need be
4. chart.js, enh I think I had trouble with this in the past, but http://tmroyal.github.io/Chart.HeatMap/ - but not updated since 2015 (https://github.com/tmroyal/Chart.HeatMap)
5. plot.ly still would work https://plot.ly/javascript/heatmaps/ - just gotta fix up styling

[CavalcanteLeo]

Heatmap and calendar, please!

Need these, any plans to release?

By now i'm using this:
https://github.com/julienr114/vue-calendar-heatmap