title: Too many warnings about 'circular require' when run rspec
body: <p>Hi I got lots of warning when run <code>rspec</code> which does annoying me too much,</p>
  
  <p>How to fix it  ? because I've tried the Ruby version <code>2.1.2</code> under rbenv, but it didn't work at all.</p>
  
  <p>Here's my Gemfile</p>
  
  <pre><code>source 'https://rubygems.org'
  
  gem 'bootstrap-sass'
  gem 'coffee-rails'
  gem 'rails'
  gem 'haml-rails'
  gem 'sass-rails'
  gem 'uglifier'
  gem 'jquery-rails'
  
  group :development do
    gem 'sqlite3'
    gem 'pry'
    gem 'pry-nav'
    gem 'thin'
    gem "better_errors"
    gem "binding_of_caller"
  end
  
  group :test, :development do
      gem 'rspec-rails'
  end
  
  group :production do
    gem 'pg'
    gem 'rails_12factor'
  end
  gem 'hirb'
  gem 'crack'
  gem 'ap'
  gem 'awesome_print'
  
  # gem 'faker'
  </code></pre>
  
  <p>Warning meassages</p>
  
  <pre><code>% rspec                                                                                                                                             (git)-[feature/w1_test_the_video_model] 
  nil
  /Users/jeff/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/bootstrap-sass-3.1.1.1/lib/bootstrap-sass/sass_functions.rb:20: warning: ambiguous first argument; put parentheses or even spaces
  /Users/jeff/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/sass-3.2.19/lib/sass/version.rb:5: warning: loading in progress, circular require considered harmful - /Users/jeff/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/sass-3.2.19/lib/sass.rb
      from /Users/jeff/.rbenv/versions/2.0.0-p481/bin/rspec:23:in `&lt;main&gt;'
      from /Users/jeff/.rbenv/versions/2.0.0-p481/bin/rspec:23:in `load'
      from /Users/jeff/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rspec-core-3.0.0/exe/rspec:4:in `&lt;top (required)&gt;'
      from /Users/jeff/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rspec-core-3.0.0/lib/rspec/core/runner.rb:38:in `invoke'
      from /Users/jeff/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rspec-core-3.0.0/lib/rspec...
  </code></pre>