1st impression of pg_shard

1st impression of pg_shard:

1. It works as described, documented limitations apply
2. Status '3' of a shard_placement means inactive, '1' means online
3. Read the issues list - unless you want to discover them yourselves :-)
4. If a whole worker node goes offline this may go unnoticed, since there seems to be no heartbeat between the head and worker nodes unless you try to write data
5. It already supports range based sharding but you have to activate it manually like so
6. It does not support prepared statements at the moment