Merge pull request #923 from jonkerz/patch-1

Replace deprecated/removed `File.exists?` alias

spec/performance/benchmark.rb

@@ -1,6 +1,6 @@
 require 'rubygems'
 ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../../Gemfile', __FILE__)
-require 'bundler/setup' if File.exists?(ENV['BUNDLE_GEMFILE'])
+require 'bundler/setup' if File.exist?(ENV['BUNDLE_GEMFILE'])
 Bundler.require :default
 
 require "benchmark"