correct the dates on the map

[mattstratton]

As mentioned in #55:

 dates are showing as "YYYY-MM-DD" vs. the existing site showing "mmm DD"

If someone wants to take this on, that's cool. I don't think it's a showstopper right now.

[davidasnider]

PR #155 submitted for date formatting

[bridgetkromhout]

This was somewhat fixed but only has start dates now. Could use end dates.

[bridgetkromhout]

Related to #882 - needs startdate math as well as end dates.

[bridgetkromhout]

Let's say Scenario 1 is to leave this as-is, which looks like this:

We've been living without both start and end dates on the map, but the problem with not showing the end date is it assumes people know these are two-day events (which maybe we should not assume).

If we want to change it, it's trivial to fix https://github.com/devopsdays/devopsdays-web/blob/master/themes/devopsdays-responsive/layouts/partials/map.html#L26:

-          ['{{ .city}}', {{ .coordinates | safeJS }}, '{{ dateFormat "Jan 2" .startdate }}', '/events/{{ .name }}'],
+          ['{{ .city}}', {{ .coordinates | safeJS }}, '{{ dateFormat "Jan 2" .startdate }}-{{ dateFormat "2" .enddate }}', '/events/{{ .name }}'],

But this is assuming we want it to look somewhat more like it did in the webby days. The down side is that single-day events (like Moscow) and events that span a month barrier (Minneapolis in this test) would look strange; let's call this Scenario 2:

Alternatively, if we keep the full month formatting, it would look like Scenario 3 here:

@mattstratton, do you have a preference?

[mattstratton]

I would go for scenario 4, which is:

1. if one day event, show only the one date
2. if spans a month barrier, show both months
3. if neither 1 or 2, show month only once.

Since this is all being opened up in the redesign, I think it's fine to tackle the right way.

[mattstratton]

The reason I say this, is in the redesign the dates of the events are displayed on the front page not only on the map element; so we need to solve for this anyway.

[bridgetkromhout]

Okay, here's what Scenario 4 looks like (with fake dates for Warsaw, as a demonstration). PR in flight - merge if this is what you wanted.