class Shoulda::Matchers::ActiveRecord::HaveDbIndexMatcher

def correct_unique?
  if qualifiers.include?(:unique)
    if qualifiers[:unique] && !matched_index.unique
      @reason = 'it is not unique'
      false
    elsif !qualifiers[:unique] && matched_index.unique
      @reason = 'it is unique'
      false
    else
      true
    end
  else
    true
  end
end