[Tagging] building=digester

[Tom Pfeifer]

Marc Gemis wrote on 2016/05/18 17:46:
> Triggered by a discussion on the Dutch forum I looked at the building
> page  [1] again. I noticed a new value: digester
>
> I wonder whether it wouldn't be better to put this under man_made [2]
> just as we do with gasometer, hot water tank and similar constructions.

Fully agree, producing biogas is a function, not a building type.
Such digester would be similar in tagging to a man_made=wastewater_plant.

Further I think that man_made=bioreactor would be easier to understand
internationally than digester.

tom