Registering entry and exit.

- Change links by submit buttons for registering entry/exit.
- Add partioned table for this month.
- Add helper methods for authentication and routes for punch the card in and out.

There's any constraint for registering entry twice. The same for exit
registration.

All the mess is on purpose and will be refactored when the time comes.
Merge pull request #10 from phcostabh/punch_card

Registering entry and exit.
Specify versions for some gems and change RSpec for Minitest.