add new version

• support legacy error message arity #2
• use os:timestamp/0 instead of erlang:now/0 #3

0.2.0: add new version

- exec each migration in transaction
- fail rest transactions if previous was failed
- add tests
- migration result now returns:
{ok, [{Version, ok}, {Version, skip}]} or throw error

{Version, ok} - if migration apply
{Version, skip} - if there's no up/down queries in migration

0.1.0: add new version

– add error formatting
– catch sql errors
– apply only pending migrations