create a new db context for each request
create a new db context for each request

otherwise we have multiple live object caches which can get out of sync
in a multithreaded server (eg starman)

robn/towncrier,fastmail/towncrier,Acidburn0zzz/towncrier,robn/towncrier,fastmail/towncrier,Acidburn0zzz/towncrier,robn/towncrier,Acidburn0zzz/towncrier