Fixing issue with resolving indexes for Postgres.

[ViagioJustin]

Not sure if this is happening on the MySQL as well but noticed when using this with Postgres that almost all generated relationships were HasMany or BelongsToMany even if there were unique keys or indexes.

Best I could tell the regex for matching the index definitions was not matching a string like:

CREATE UNIQUE INDEX addons_product_id_unique ON public.addons USING btree (product_id)

It seemed like the regex was expecting something like:

CREATE UNIQUE INDEX addons_product_id_unique (product_id)

And maybe that's a MySQL syntax? Not sure. But changing the regex here seemed to correctly detect unique indexes and then bubbling up to the generator when determining if a relationship is a HasOne/BelongsTo or HasMany/BelongsToMany.