add rspec to Gemfile and specific ruby version in rvmrc
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Added Cash Register Kata

This is a short kata which introduces the user to the knapsack problem.
Added requirements for Change class.
Added requirements for Change class.
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' of github.com:spinlock99/code_katas

Conflicts:
	cash_register.rb