fixes the days calculation
makes the expense table look better
adds bank-of-israel gem
adds a server endpoint for getting the maximum exchange rate for a given currency between two dates
adds a rateService to interact with the rates endpoint
adds spin.js and blockUI.js to be used when the rate is fetched
adds a calculation method for the expense sum in local currency
adds a local sum column, number formats for currency and starts to use form validation
adds a spinner and block the user while the rates are being fetched
uses the rateService to actually update the exchange rate when needed