class Hash

def transform_keys

# => { "NAME" => "Rob", "AGE" => "28" }
hash.transform_keys{ |key| key.to_s.upcase }

hash = { name: 'Rob', age: '28' }

Return a new hash with all keys converted using the block operation. 
def transform_keys
  result = {}
  each_key do |key|
    result[yield(key)] = self[key]
  end
  result
end