ActiveSupport::CoreExtensions::Hash::ReverseMerge

Allows for reverse merging where its the keys in the calling hash that wins over those in the other_hash. This is particularly useful for initializing an incoming option hash with default values:

  def setup(options = {})
    options.reverse_merge! :size => 25, :velocity => 10
  end

The default :size and :velocity is only set if the options passed in doesn't already have those keys set.