Eugene prototype

Progress so far:
- Updated all fare and commission general formulas to use retrieve constants from activerecords.
- Generated two simple controllers for both fare and commission to return a json that states the return value of the calculator.
- Generated models for Fare, Commission, Booking and Driver. Created a simple factory that creates a booking object.
- Tested the flow of prototype (from url -> controller -> call the right calculator -> calling the right general formula (without models)
- Tested validity of current formulas (without using models yet).