Karlsruhe: Add location for markets

[wo-ist-markt]

Karlsruhe: Add location for markets

[johnjohndoe]

I close this issue since we decided that the location field is optional.

[torfsen]

Is there a reason why location cannot be null? In my understanding it always was an optional field that could be used to specify the precise location in case the (mandatory) title was not enough. In the cases you listed the title is precise enough, so there's no need for further information.

See also #27.

[johnjohndoe]

In an ideal data setup title should contain the well known name of the market as in Kirchenmarkt Rüppurr or a type qualifier as in Trödelmarkt Oberreut. The location field should provide detailed address information as in Auf dem Julius-Leber-Platz or Vor der Christ-König-Kirche.

[torfsen]

I see you point, but on some markets there is simply no difference between these two. Of course I can use a title of Wochenmarkt Werderplatz and a location Auf dem Werderplatz, but for me that's just clutter compared to simply using a title of Werderplatz, in particular since we only cover traditional farmer markets in Karlsruhe.

I like your addition of a validation step, but I do think that we should keep location optional.

[johnjohndoe]

@torfsen I refactored the validator to differentiate between warnings and errors.