title: RSpec can't find nested formatter
body: <p>I am trying to run <code>rspec</code> only for Ruby (not Rails), for a simple Ruby file. I'm following Tut+ TDD Testing with Ruby.</p>
  
  <p>I have a <code>competition</code> directory with a <code>lib</code> folder and <code>spec</code> folder.</p>
  
  <pre><code>├── lib  
  │   ├── competition.rb  
  │   └── team.rb  
  └── spec  
      └── competition_spec.rb  
  </code></pre>
  
  <p>When I run <code>rspec</code>, I got this error.  I could've sworn the rspec work before.  I don't know what happened.  </p>
  
  <pre><code>competition :&gt; rspec spec
  /Users/akh88/.rvm/gems/ruby-1.9.3-p547/gems/rspec-core-&gt; 3.0.2/lib/rspec/core/formatters.rb:167:in `find_formatter': Formatter 'nested' unknown - maybe you meant 'documentation' or 'progress'?. (ArgumentError)
  </code></pre>
  
  <h3>My <code>competition_spec.rb</code></h3>
  
  <pre><code>require_relative "../lib/competiiton.rb"  
  require_relative "../lib/team.rb"  
  
  describe Competition do
    let(:competition) {Competition.new}
    let(:team) {Team.new}
  
    context "having no questions" do
      before { competition.questions = [] }
  
      it "doesn't accept any teams" do
        expect do
          team.enter_competition(competition)
        end.to raise_error Competition::Closed
      end
    end
  end
  </code></pre>
  
  <p>My <code>rvm</code> default Ruby version is 1.9.1 on Mac OSX 10.9.4.</p>