Time columns don't handle timezone correctly

When saving to a :time column, the value is converted to the database timezone (expect UTC in a normal setting).

When reading the value back from the database, the time value has no timezone (since time fields don't store this information) and the value is read back verbatim, and thus shifted.

I'm working around this with the following accessor:

def mon_open
  self[mon_open] && self[mon_open].in_time_zone
end