Add a SWIFT class file to the project that illustrates and contains the following:
• The class name is 'Calculator'
• Has public variables of the type float called numerator, denominator and total.
• Has a method called 'Add' that returns the sum of numerator and denominator and sets the total variable.
• Has a method called 'Divide that returns the division of the numerator and denominator and sets the total.
• The 'Divide' method should contains a 'try/catch' to ensure that dividing by zero is addressed.