Set defaults for rollback to delete records. Add columns that hold error stacktraces
Fix rollback table.

According to the latest changes in rollback script.
README update
Use correct dates during rollback
Fix rollback related specs

Conflicts:
	spec/integration/tariff_synchronizer_spec.rb
Merge pull request #184 from bitzesty/default_rollback_and_error_tracking

Set defaults for rollback to delete records. Add columns that hold error...