fill in History for 1.2.9
[postgres] only type_cast on AR 4.0 + AR 3.1 column definition compatibility
[postgres] restore <= 3.1 compatibility with IndexDefinition#new args size
[postgres] primary_key definition for AR-4.0
tests for postgres primary_key issue when there's no sequence (see #356)
Always return correct primary key from postgres

The previous implementation failed when the primary key
had no sequence (eg UUID)

Used the code from rails 3.2