Modified to implement postgres adapter and...

...postgres sql changes

567 examples, 0 failures
Coverage report generated for RSpec to /Users/yzhang/the_policy_machine/coverage. 624 / 702 LOC (88.89%) covered.
Passes with mysql and postgres backends
Passes specs in dalton postgres branch with this commit on postgres, mysql and memory backends
Discussed offline, we want to remove this line and change the variable name since we're not necessarily paginating.