Removed deprecated usage of simple_from class without wrap_with in a custom inline_checkbox input.
Added link to create new tariff.
Added layout and styles for new tariff page. Adding of new tariffs is not working yet.
Removed placeholder for tariff end_date.
Fixed date parsing for new tariff form. Used 'chronic' gem to parse not only russian date format but also natural language dates ( such as today, 2 years ago, etc). Russian language does not supported yet.