Pgsql output deprecated and will be removed in a later version

[balchen]

Overv/openstreetmap-tile-server currently uses the Pgsql processing output. This output has been deprecated by osm2pgsql in favour of the Flex output. Some features that are part of Flex will not be made available in Pgsql, such as processing ways based on their membership in a route.

Osm2pgsql recommend that all new projects use the Flex output.