Extract primary key constraints hash to a method.
Extract primary key constraints hash to a method.

Since this hash will need to change in the future to support composite
primary keys.

joonyou/rails,bogdanvlviv/rails,Envek/rails,kmcphillips/rails,georgeclaghorn/rails,yahonda/rails,kddeisz/rails,lcreid/rails,betesh/rails,rails/rails,yawboakye/rails,BlakeWilliams/rails,BlakeWilliams/rails,kmcphillips/rails,EmmaB/rails-1,Vasfed/rails,betesh/rails,joonyou/rails,betesh/rails,rails/rails,esparta/rails,BlakeWilliams/rails,lcreid/rails,georgeclaghorn/rails,MSP-Greg/rails,bogdanvlviv/rails,joonyou/rails,MSP-Greg/rails,georgeclaghorn/rails,kddeisz/rails,georgeclaghorn/rails,bogdanvlviv/rails,BlakeWilliams/rails,yawboakye/rails,yahonda/rails,Erol/rails,Stellenticket/rails,MSP-Greg/rails,Erol/rails,betesh/rails,Envek/rails,yahonda/rails,rails/rails,Stellenticket/rails,Edouard-chin/rails,lcreid/rails,MSP-Greg/rails,Vasfed/rails,Edouard-chin/rails,kmcphillips/rails,esparta/rails,lcreid/rails,bogdanvlviv/rails,kmcphillips/rails,joonyou/rails,yawboakye/rails,Stellenticket/rails,kddeisz/rails,rails/rails,esparta/rails,Envek/rails,EmmaB/rails-1,Stellenticket/rails,Edouard-chin/rails,yawboakye/rails,Edouard-chin/rails,esparta/rails,kddeisz/rails,EmmaB/rails-1,Vasfed/rails,Vasfed/rails,Erol/rails,yahonda/rails,Envek/rails,Erol/rails