Support updates on data not managed by Phabric

[benwaine]

Currently only updating values that were inserted by Phabric Is supported. Add ability to update other elements of the fixture.

My personal opinion here is that only structure should be added in the initial sql fixture and perhaps some boiler plate data (like an admin user). However after talking with a few others it seems this functionality is in demand.

[cordoval]

yeah I also vote for this, i was just trying to use relational data insert that was related to items in other child tables that i would like were pulled from data which is existent on db or that has been just persisted to db