v2.1.5

Bug fixes

• #77 Unique definitions were not correct in that if a unique key was placed over two columns, each column became unique which shouldn't be the case. This resulted in relationships generating one-to-one where they should have been to-many.
• #85 Fixed an oversight in Postgres where information_schema doesn't provide enough information to uniquely identify a duplicated constraint name causing multiple relationships to be generated.
• #84 Fixed a postgres-ism where no data is returned from a query when there was no data updated in an upsert which would return a spurious error.