data redundancy or not?

Hi, perhaps a bit off topic but i realy want to know what you rails people think of the following situation:

i am building a shift trading application, so i have a table with shifts and a table with transactions.

in the transactions table i keep track of the movement of shifts between users. i have the fields from_user, to_user and status the status can be - offered for trade (1) - in negotiation (2) - transaction completed (3)

so, when i take a shift, i can always determine the status of it as follows: if there are no associated records in the transactions table, i can offer it for trade. i can also do this when there are no transactions with status 1 or 2

of course this is not too complicated to figure out, but adding an extra status field on the shift recored is much easier to work with.

so: what would you do? add the extra field or keep the design clean?