[bug] redeem got http 500 error with postgresql

[ma-joel]

with the fix of unable to login provided here, I can login and create key, challenge also works fine, but when it comes to redeem the response is http status 500 and message:

column reference "count" is ambiguous

bug description:
a clear and concise description of what the bug is and how it happened.

affects:

• standalone
• [] widget (ui)
• [] widget (wasm solver)
• [] js server
• [] js solver

to reproduce:
setup standalone docker with pg connection
create key
start challenge from widget ui
got 500 when post to /{key}/redeem

expected behavior:
respons ok

screenshots:

versions and environment:
image version 2.0.18

additional context:
add any other context about the problem here.

[tiagozip]

please note that postgres support is very experimental, i would recommend keeping SQLite for now.
to focus all issues with postgres into a single issue, i'll close this as a duplicate of #136