module Hashie::Extensions::DeepMerge

def _recursive_merge(hash, other_hash)
  if other_hash.is_a?(::Hash) && hash.is_a?(::Hash)
    other_hash.each do |k, v|
      hash[k] = hash.key?(k) ? _recursive_merge(hash[k], v) : v
    end
    hash
  else
    other_hash
  end
end

def deep_merge(other_hash)
  dup.deep_merge!(other_hash)
end

def deep_merge!(other_hash)
  _recursive_merge(self, other_hash)
  self
end