Ruby 使用rack Mini Profiler 来分析和优化rails

参考 ： https://github.com/MiniProfiler/rack-mini-profiler

以及: 这个: 特别有意思, 写的特别好:  https://stackify.com/rack-mini-profiler-a-complete-guide-on-rails-performance/

1. Gemfile: gem 'rack-mini-profiler', require: false

2  bundle exec rails g rack_profiler:install

会生成文件 config/initializers/rack_profiler.rb  内容如下：

if Rails.env.development?
  require "rack-mini-profiler"

  # initialization is skipped so trigger it
  Rack::MiniProfilerRails.initialize!(Rails.application)
end