class Gem::Specification

def add_bundler_dependencies(*groups)
  groups = [:default] if groups.empty?
  Bundler.definition.dependencies.each do |dep|
    if dep.groups.include?(:development)
      self.add_development_dependency(dep.name, dep.requirement.to_s)
    elsif (dep.groups & groups).any?
      self.add_dependency(dep.name, dep.requirement.to_s)
    end
  end
end