Hash deep merge

gistfile1.rb

class Hash

  def deep_merge(other_hash)
    Hash.new.replace(self).tap do |new_hash|
      new_hash.deep_merge!(other_hash)
    end
  end

  def deep_merge!(other_hash)
    each do |key, val|
      if val.is_a?(Hash)
        next unless other_hash.has_key?(key)
        val.merge_tree!(other_hash[key])
        val.merge!(other_hash.delete(key)) if other_hash[key].is_a?(Hash)
      end
    end
    merge!(other_hash)
  end

end