- Destructure the `calculateMonthlyPayment()` function
- Replace *all* instances of `let` with `var`
  to achieve the desired block scoping instead of
  variable scoping
- Declare a new function called `calculateAmortization()`
  that calculates the amortization for each month
- Insert an additional inner HTML when the `calculate` button
  is pressed.

 Changes to be committed:
	modified:   index.html
	modified:   js/main.js

- Set up webpack and created the necessary config file
- Separate the `monthlyPayment` and `amortization` functions
  into separate class `mortgage.js` and import it to `main.js`
- Make some changes to the function that fires on the click
  of `Calculate` button so as to show bar graphs of progression
  of payments that need to be made
 Changes to be committed:
	modified:   index.html
	modified:   js/main.js
	new file:   js/mortgage.js
	modified:   package.json
	new file:   webpack.config.js

- Modify `webpack.config.js` to handle the additional
  HTML page to be parsed
- Create `ratefinder.js` that is called directly by the
  `ratefinder.html`
- Create `rate-service-mock.js` that is uses promise
  to get data from a mock JSON objects.