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 specs in dalton postgres branch with this commit on postgres, mysql and memory backends
I don't think it's a good idea to add a .rvmrc to a gem. If the_policy_machine has a ruby version dependency that should be reflected in the gemspec as unrestrictively as possible.