Resolve the issue with ConditionTier table duplicate inserts.

[Synicix]

There has been an issue with inserting values into the ConditionTier table where it seems sometimes it complains about duplicates, cause at one point that was already assign to either train, val, or test before. This might require a redesign but the current patch is skip_duplicates when inserting. Not ideal, but would be nice if someone can take look at this at some point.