posterior_id and ensemble_id where ints instead of bigint.

mistake, had all foreign ID's as ints, not bigints.
I don't know how I let posterior_samples slip through, but is it too late to follow Rails convention and call this table (and associated class) posteriors_samples?  Or do you have a lot of Pecan code that depends on it already?  Sorry for being so OC but I curse every time I see "specie" in the code, and I don't want to have another reason to curse.