[Merge on 1st October before 10 AM] Minimum wage rates - Add Oct 2014 - Sep 2015 Minimum Wage rates

- 21 and over: £6.50
- 18-20: £5.13
- under 18: £3.79
- Apprentice: £2.73
- Accommodation rate: £5.08

https://www.agileplannerapp.com/boards/105200/cards/6141

This changes have been already reviewed here:
https://github.com/alphagov/smart-answers/pull/1152
I merged the previous PR by mistake before October 01, this is why I created this one.

I would appreciate if someone could give a look at this once again.