add money-rails

Do not use floats to represent currency
http://stackoverflow.com/questions/3730019/why-not-use-double-or-float-t
o-represent-currency
add `CierreCaja`
minor client-side enhances
be more strict with routes
`Bandango.CierreCaja`
`CashDenomination`
seeds for `CashDenomination`
`CashDenominationItem`
`CierreCajaOrder`
minor server-side enhances
extend `ApplicationSerializer`