class Hash

def smash(prefix = nil)

hash.smash # => {"a"=>1, "b-c"=>2}
}
'b' => {'c' => 2},
'a' => 1,
hash = {
converts a deep hash into a flat hash 
def smash(prefix = nil)
  inject({}) do |acc, (key, value)|
    index = prefix.to_s + key.to_s
    if value.is_a?(Hash)
      acc.merge(value.smash(index + '-'))
    else
      acc.merge(index => value)
    end
  end
end