Update readme for exercise 'accumulate'
Update readme for exercise 'accumulate'

Insti/exercism-ruby,Insti/exercism-ruby,exercism/xruby,NeimadTL/ruby,NeimadTL/ruby,Insti/exercism-ruby,exercism/xruby,Insti/xruby,NeimadTL/ruby,Insti/xruby