And keep the fields updated, by copying on UserProfile creation and
updating the UserProfile object whenever we're updating the User
object, and add management commands to (1) initially ensure that they
match and (2) check that they still match (aka that the updating code
is working).
The copy_user_to_userprofile migration needs to be run after this is
deployed to prod.
(imported from commit 0a598d2e10b1a7a2f5c67dd5140ea4bb8e1ec0b8)
This cuts the time required to import 38000 messages (with 140000
message receipts) from about 10 minutes to just under 40 seconds on my
laptop with sqlite.
(imported from commit d53b0d1360408c77f38353b58fbb25875262cb40)
